The Volokh Conspiracy
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Knee Defenders and Virtual Laps—Part 1
On a crowded flight, is there a right to recline or a right to defend your knees? And what does this teach us about the hidden rules of ownership?
This post is adapted from our new book, Mine!: How the Hidden Rules of Ownership Control Our Lives.

Who owns the space behind your airplane seat: you reclining or the squished laptop user behind? And who owns your online life: you clicking around or Facebook selling your most intimate data?
Turns out, these puzzles are both the same puzzle and they share a single answer: you lose. The prize goes to those who know how the simple rules of ownership really work.
James Beach is a large guy, over six feet tall. On a United Airlines flight from Newark to Denver, the businessman lowered his tray table and attached his Knee Defender. The Knee Defender is a simple plastic clamp available for $21.95 that locks the seat in front. Its website claims the clamp will "stop reclining seats on airplanes so your knees won't have to." Assured of his workspace, Beach opened his laptop.
The Knee Defender claims are real. When the passenger sitting in front of Beach tried to recline, her seat didn't budge. Outraged, she slammed her seat back, popping out the Knee Defender and jolting Beach's laptop. He quickly jammed her seat back up and reattached the clamp. She turned around and threw her drink at Beach. The pilot changed course to Chicago for an emergency landing and both passengers were removed from the plane.

These high-altitude brawls are happening more and more. Last year, on an American Airlines flight from New Orleans to North Carolina, Wendi Williams reclined her seat. The man behind was in the last row, so he could not recline. Instead, he tapped the back of Williams's seat repeatedly, like an irritating metronome. Her video of this high-altitude fracas quickly went viral.
After each incident, the blogosphere boomed back and forth with indignant commentary. Talk show host Ellen DeGeneres defended Williams: "The only time it's ever okay to punch someone's seat is if the seat punches you first." Delta Air Lines chief executive Ed Bastian took an opposing view: "The proper thing to do is, if you're going to recline into somebody, you ask if it's OK first." Williams didn't ask.
So who's right?
Williams's view is simple: her armrest button reclines her seat, so the space belongs her. My home is my castle, and anything attached to it is also mine.
Attachment is the most important ownership principle you've never heard of. It's why landowners in Texas can extract underground oil, why California's Central Valley is sinking, why Alaska can sustainably manage Bering Sea fisheries—and why occasional homeowners feel justified in shotgun blasting drones hovering above their backyards. Attachment is what translates two-dimensional boarding passes, land deeds, and maps into three-dimensional control of valuable resources.
But attachment is not the only ownership rule in play. At the beginning of every flight, all seats are in the "full, upright, and locked position." At that moment, Beach had exclusive use of the space in front of him. He had first dibs on the wedge. First-in-time is a second core rule for claiming mine. Kids assert it on the playground; adults invoke it up in the air. It's mine because I was first. Recall that Beach actually took physical control of the wedge with his Knee Defender. And there's a third rule. Possession. Nine-tenths of the law. Mine because I'm holding onto it. Possession means I get to defend my workspace.
Air travel brings into sharp focus three conflicting rules—attachment, first-in-time, and possession.
Each side picks the story that gives it the moral high ground, each side wants ownership bent toward its view. But there is no natural, correct answer to mine versus mine battles. Ownership is always up for grabs.
When we ask audiences about the Knee Defender conflict, the answer is always the same, whether we're talking with our law students at Columbia and UCLA or a non-law crowd. Most people respond with versions of "It's obvious." But when we ask for a show of hands, people generally split between Williams and Beach—and everyone looks at each other with incredulity. In a 2020 national poll, about half replied, "If it can recline, I'm reclining," and the other half said, "No, just don't do it." Everyone feels in the right, as did Williams and Beach. That's why Williams felt justified in posting her video and Beach didn't hesitate to shove the front seat forward. Don't mess with what's mine.
Tomorrow, in part 2, we explore why these high-altitude brawls are breaking out now and how deliberate ambiguity is an advanced tool of ownership design. Part 3 will show how the Knee Defender story explains everything from how the West was settled a century ago to battles today over who owns our online data.
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You have a right to follow the rules of whoever owns the airplane.
but what are the rule? there are none! See: https://priorprobability.com/2014/10/07/8726/
You have a right to be a jerk, but so do others. These people need remedial kindergarten.
but who is the jerk? it depends on who has the right to recline or the right to space, and that right is not well-defined! See: https://priorprobability.com/2014/10/07/8726/
Being right doesn't mean someone isn't a jerk. Both the person seeking to recline and the person defending can be jerks. Alternately, a person can politely look around and recline if clear, and a person can reasonably ask that the other person not recline, perhaps for good reason such as long legs. The solution is not more one-size-fits-all rules and definitions, but more recognition of common humanity.
Probably the divide is along the lines of height - taller people with longer legs have their knees shoved into their pelvis. Since this doesn't ever happen to shorter people, they choose to believe it never happens.
"People reclining in front of me present no discomfort to me, so my reclining can never cause discomfort to another."
Politeness plays no part here.
Could a man who observes a woman giving birth understand that her activity is painful?
The contracts giving away those rights to personal information are unconscionable in procedure and in substnce, and void. Due to the size of these services, they are monopolistic utilities, subject to regulations. Payment can be enforced by regulation. Someone should retrieve the value of the personal information from the tech billionaires, around half their total revenues ever earned.
The space in an airplane is not possessed by the flyer. It is possessed by the airline, and their rules apply. I know lawyers are dumbasses, by these points are obvious to the ordinary non-lawyer.
Hush; the grownups are talking.
In this scenario, I'd say Beach loses the fairly justiciable issue.
The space all belongs to the airline, Beach and the woman are tenants. They have ben granted a license to a seat manufactured with a normal range of motion backward - Beach's seat also reclines into the space behind him.
Beach bought a device that increased his space to the detriment of another passenger, whose consent he didn't obtain. So I rule that he loses this trivial contest. Referring this to the serious readers en banc for their insights, however.
That's my analysis as well, with the qualifier that Beach's seat's ability to recline is irrelevant. He could, for example, be in the last row that doesn't recline. The airline is renting the space with the expectation of reclining. Users have no right to infringe on that contract.
That said, I have little sympathy for the Williams' of the world who slam their chairs back with no notice, shoving my laptop, my carefully balanced papers and my drink into my groin. Those people deserve to be strangled with the oxygen mask. Or maybe given very spacious seats out on the wing.
By the way, possession sucks as a rule for "what's mine" because it inevitably leads to 'might makes right'. Possession only matters if you can keep possessing it. I suppose it has to be listed as a theoretical underpinning to the concept of "mine" but I hope the articles elaborate and move past it.
Option 3: Airlines lock all the seats in place and that's it.
Which place?
Some airlines already do. Frontier for one.
Indeed! That solves the problem for all reclining seats, especially in cattle class are a hazard for all
Great post, reminiscent of what I remember from the heyday of the VC. Looking forward to reading the follow-on posts, and more like this, please.
(withholding comment on the seat-recline issue for now)
You hit a pet peeve of mine.
What triggers me most is for those people who recline, they don't do so before checking behind them to see if they space they are invading has anyone/anything there first. The seat-belt light goes off then wham! they mash that button and slam back full force. Not the slightest awareness of anything in the world but themselves.
Best case rule is the seat recliner should be used only if the seat behind you is empty. Just like a realistic national health policy, there is little to no chance of that ever being implemented.
but see: https://priorprobability.com/2014/10/07/8726/
invading
You gave away your game, right there.
Fault here lies with the airlines.
The airlines should be forced to compensate both Beach and the woman who was sitting in front of him.
The problem ultimately is that the airlines keep trying to stuff more and more passengers in the same size aircraft. Seats have been getting narrower, which is a problem for "persons of mass" and the distance between rows has also been shrunk.
The airlines should either be required to switch to non-reclining seats or to provide enough space between rows so that a seat can be fully reclined without interfering with the comfort of the passenger in the next row back, even if that passenger is the tallest person in the world.
That and their installation of the seats too close togeather.
I said that: "and the distance between rows has also been shrunk."
And you'll pay me the marginal difference between the ticket price I'm paying now, and the higher price I'll have to pay when your "compensate both" rule obliges the airlines to reduce the number of seats on board, regardless of market demand and preferences?
If so, please post your contact info so I can invoice you appropriately. If not, then your argument fails.
"the airlines keep trying to stuff more and more passengers . . . ."--If you don't like what the Conspirators write, you don't have to read their blog. If you don't like Amazon refusing to sell certain books on ideological grounds, then buy your books somewhere else. And if you don't like air travel as it is currently offered, don't fly. (Or fly first class.)
The Knee Defender is a piece of equipment installed in an airplane illegally. It's not FAA approved, and there's not STC allowing its installation, and the owner of the airplane hasn't consented to its installation, either. I think people using these things should be charged with crimes.
If you need more space, but an economy-plus, business class, or first class seat, don't presume to take away another passenger's comfort for your own.
Re STC: Umm, no. Unless that first paragraph is meant to be sarcasm, in which case, well done!
Not sarcasm, at all. Did you know that even seat belt extenders require STCs?
Refusing my consent for the passenger in front of me to recline into my space is not taking anything away from them. I am entitled to the comfort I paid for, and that includes the space into which they wish to recline.
Sorry, not sorry that I'm going to recline my seat when you're sitting behind me. If you want more room, buy a roomier seat ticket.
So, because the airline gives you the ability to injure another person, you now think it is your right...
You paid for the seat. Presumably that means that you paid for the space that the seat is capable of occupying, regardless of whether or not you have it configured to occupy that space at any moment.
That's sort of my position. (When I recline my seat, I do it slowly.) I have a significant lower-back issue (including multiple spinal surgeries) and I would not fly with a seat that did not recline, for any flight over 2 hours. It's something I carefully check on before the flight, and pay extra for--when necessary--to ensure that I do not get stuck with one of those non-reclining seats.
It would be unacceptable for me to be told, on a 6-hour cross-country flight, "Sorry, but we needs you to not recline your seat, due to the needs of the person behind you." I'm not willing to risk 2 weeks on my back, recovering from this flight. Sadly, there's no way (yet?) for the airlines to factor this in, so that a "must recline for medical reasons" will not be put directly in front of a "must not be behind a reclining seat, for medical reasons." 🙂
It's one of those situations where you have a lot of empathy and sympathy for both sides. I have less sympathy for those who want the extra legroom just so they can do work or watch a movie on their laptop, and I have tons of sympathy for the very tall or very fat, who just need that extra room to exist in the world.
It's all a result of airlines cramming in more and more seats, so I absolutely have zero sympathy for the airlines.
The passenger behind you is entitled to their space, and they have no obligation to give it up to accommodate your medical issues. If you can't sit in a normal upright position for an X-hour flight, then you shouldn't be flying for X-hours. But I swear if you ever end up in front of me, you will get your sorry ass kicked off the plane.
Wow, an internet tough guy.
If the passenger behind me is entitled to the space, how come my seat is configured to move into it when I push a button?
Because they may be ok with that if you ask, or you may get lucky and not have anyone behind you on a particular flight?
You are completely missing the point of the article by assuming that the laptop space is "your" space in the first place. On what basis is that wedge-shaped volume of space "yours" and not owned (or more precisely, rented) from the person in front of you.
Maybe here's a better suggestion for you Santamonica811: If reclining matters so much to you on long flights, then whenever you are going on a long flight, book two seats: If you pay for the seat behind the one you intend to sit in, then surely you can recline into that space without impinging on the space that other flyers have paid for.
Or, if you have a problem with the guy in front of you reclining into the space that he paid for, you can buy a ticket for the seat in front of you?
That's one possible presumption. Another is that the airline only intends for its passengers to use the reclining function built into the seat when they can do so without discomforting the passenger behind them, or when that seat is empty. That's actually more in keeping with the social norms, which are that everyone try to avoid aggravating everyone else. Only an intrinsically selfish person would argue that just because he physically can do something, it's appropriate for him to do that regardless of other circumstances.
Another is that the airline only intends for its passengers to use the reclining function built into the seat when they can do so without discomforting the passenger behind them, or when that seat is empty.
If that's what the airlines intended, they could have built a function in the seats for a passenger to prevent the seat in front of him from reclining, or they could announce the reclining rules.
In fact, they do announce some rules about when you can recline (not during takeoff and landing) but they don't announce the one you suggest.
Undefined property rights, anyone?
This may be the fault of the airlines for not being clear about the rules. It could be a marketing problem. You don't want to tell passengers they can't recline, and you don't want to tell them the passenger in front can come back into their space, so say nothing, and hope for the best.
"This may be the fault of the airlines for not being clear about the rules."
I'm pretty sure it's the fault of the people involved.
And I suspect that one reason that the airlines are not clear about the rules is that, in 99.9999% of the cases, it isn't a problem. But if they make rules, they'll be asked to enforce them.
It's the fault of the airlines for providing relining seats, but not providing enough space to recline the seats fully without interfering with the comfort of other passengers.
So, why not have clear rules? In the 99% of the cases where there's no issue; the airline obviously will say, "You two can do whatever you want, since you're both fine with X." But when there is a dispute, it would immediately de-escalate things and end the dispute if the flight attendant could pull out the rule book, politely show the rule to the passenger at fault, and say, "Sorry, but this is the rule. And it was clearly given on the website when you bought the ticket. Can I bring you a complimentary beverage?"
"politely show the rule to the passenger at fault, and say, “Sorry, but this is the rule. And it was clearly given on the website when you bought the ticket. Can I bring you a complimentary beverage?”
I like this approach.
As I understand, airlines (who own the seats and the space around them) have banned the knee defender. https://www.huffpost.com/entry/knee-defender-ban_n_5723136
+100
https://priorprobability.com/2014/10/07/8726/
Yes. Coase again.
The passengers have a right to recline if the airlines design the seats that way, but the passenger in back have a right to passive aggressively "accidentally" kick and bump the seat in front who is rudely reclining every few minutes.
Is that a real problem? I've flown literally hundreds of times, and I've never seen a case where someone is reclining a seat every few minutes. (If it happens; of course that person is doing it to be an asshole and deserves the blame.)
You're confusing what someone may get away with with what someone has a right to do, and your use of an oxymoron ("passive aggressively") and the quote marks around "accidentally" (in this context, to indicate that there's no accident involved, but rather intentional behavior) proves your argument wrong.
Well, you've promised a lot for the next two installments. I'm looking forward to reading them....
I'm still wondering if he got an alcoholic drink in his face, and if a special type certificate applies to a gadget like a klunky knee defender that doesn't work.
And why punish the entire population of passengers with an unscheduled stop and a delay because two passengers are juvenile delinquent jerks? I say manacle with zip ties and gag both of them and fly on to the destination. Or how about a special cubicle on the aircraft where both of them could be hogtied, gagged, xanaxed, and held until after the aircraft lands?
It was soda.
https://www.cbc.ca/news/world/knee-defender-passenger-ashamed-but-won-t-stop-using-airline-seat-gadget-1.2754863
The answer to this is simple. Seats are "Upright" at takeoff to not block the aisle behind them in case of an evacuation. the angle of the seat is way too upright to be comfortable for a flight even for those without back problems. The space behind is there for the seat to recline to an angle that is passably comfortable for the occupant. If someone need to use a laptop in a flight for work, they should fly business class an not force others to sit for hours in uncomfortable chairs.
" the angle of the seat is way too upright to be comfortable for a flight even for those without back problems."
Based on 6 million miles of flying, I say that your statement is nonsense unless you're 1.8 meters tall or more.
About half of all adult men are 1.8 meters tall, or taller (the median height is actually 178.4cm).
You're right. I should have said 2 meters.
I'd prioritize an airline, at least on flights under four hours, which either locked the seats upright (such as Frontier?) or which had a policy along the lines of:
Ultimately, it would be ideal if another control was added which would allow the passenger behind to lock out (or restrict to x%) the reclining ability of the seat in front of them. Some mechanism to reset these controls to "allow recline" between flight segments would probably be needed so the last passenger's preference didn't prevent reclining into a vacant seat. However such controls would add weight, complexity, and maintenance costs so it's unlikely airlines would buy such seats.
More important question, are lawyers allowed object to jurors on the basis of height?
And no mention f the lovely child behind you that thinks it is so much fun to repeatedly bang the seat in front?
What's obvious to me is that both the airline passengers are limited-purpose licensees aboard that aircraft, and they board it subject to whatever laws and regulations govern passenger flights and, to the extent not in conflict therewith, whatever rules and stipulations mandated by the airline.
Only if all of the above are silent does anyone's hunch as to what's right come into play. I really do NOT think your seat-of-the-pants (and knees-of-the-pants) analysis is closely analogous to the rule of capture with respect to underground mineral rights.
Having read this (and having become interested in reading the book), I pause to consider the fact that the fifty-fifty-split is as powerful as is the ability to manipulate the power of the fifty-fifty-split. For lack of a better term, it is the Tom Sawyer effect.
Fourteen months ago, who would have thought a pocket of Americans would approve of a bonus for "essential workers" without such pocket first acknowledging its own non-essential status? Really, did anyone imagine a posse walking down the street chanting "I'm non-essential!! Long live the essentials!"?
Perhaps Gene Roddenberry had the right idea: The Menagerie cannot be kept and instead exists only as the household -- the ménage -- its name suggests. What if a fifty-fifty splits suggests not compromise but comportment -- comportare, com- ‘together’ + portare ‘carry, bear’.
"Because the FAA does not specifically ban devices like the Knee Defender, individual airlines are left to decide whether or not they allow the device. According to the Associated Press, United and all other major U.S. airlines have banned it."
Or, they are meant to recline under certain conditions - when the seat behind is empty, or the passenger gives permission, say, or maybe just a little otherwise.
It doesn't necessarily mean they are meant to recline under all circumstances.
That's one inference, and probably a sound one. On the other hand, when we're untethering ourselves from any laws, regulations, or even airline rules and just spit-balling about "what's right," an equally valid inference is that the airline intends its passengers to recline if, but only if, they can do so without causing physical discomfort to the passengers behind them.
I haven't done the research to rule out the possibility that there are federal regulations or something in the airline tariffs which limits airline flexibility on this topic. (That research is something these authors surely should have done; I'm curious why this first essay in their series doesn't mention whether they did it, or if so what the results were.) But assuming that the law doesn't impose rules that the airline can't vary, then it would be a good thing — it would reduce conflict and avoid flight diversions — for airlines to post their own actual policies, via conspicuous signage in the boarding areas and aboard the aircraft, to so advise their customers.
Bingo! +1 for this.