"Once the Cat Is Out of the Bag, the Ball Game Is Over."
More than just a mixed metaphor -- it's a legal doctrine.
Several months ago, I quoted an opinion (U.S. v. Suppressed) that referred generally to such mixing of metaphors:
To the court's great regret, although the search warrant affidavit was at all relevant times subject to an order that should have guaranteed its protection under seal, … the subject affidavit was not at all times properly sealed. That its disclosure was the result of a docketing error that was corrected upon its discovery does not change the fact that the document was temporarily accessible to the public, and during that temporary period of accessibility the Sun-Times exploited the error and downloaded the affidavit. The Sun-Times has since published extensively on the affidavit's contents.
As the Tribune puts it in a collection of mixed metaphors, post-publication "the genie is out of the bottle," "the cat is out of the bag," and "the ball game is over." There is no step that this court can take post-publication of the search warrant affidavit's details to regain the secrecy of the publicly disseminated information.
But it turns out that the Second Circuit has expressly described the rule precisely this way, humorously but seriously, see Gambale v. Deutsche Bank AG (2d Cir. 2004):
[I]t was a serious abuse of discretion for the district court to refer to the magnitude of the settlement amount — theretofore confidential — in the Unsealing Order. But however confidential it may have been beforehand, subsequent to publication it was confidential no longer. It now resides on the highly accessible databases of Westlaw and Lexis and has apparently been disseminated prominently elsewhere. We simply do not have the power, even were we of the mind to use it if we had, to make what has thus become public private again. The genie is out of the bottle, albeit because of what we consider to be the district court's error. We have not the means to put the genie back.
[Footnote:] Once [information] is public, it necessarily remains public. As Judge Richard Owen, of the United States District Court for the Southern District of New York, once aptly reminded the author of this opinion while he was acting as counsel for a party at trial: "Once the cat is out of the bag, the ball game is over."
Unsurprisingly, other courts have picked up the phrase.
This principle doesn't always prevail; sometimes, courts do retroactively seal documents that had been erroneously disclosed, especially if the error is recognized quickly, the error wasn't the objecting party's own fault, and the document's contents haven't been prominently picked up by others. I've even seen courts retroactively seal published decisions, and ask (though they can't order) Westlaw, Lexis, Google Scholar, and the like to withdraw them; the decision may remain in print, but this way it becomes less likely to be found online. But the cat/ball game principle is at least a substantial thumb on the scale for many courts.