Gun controllers like to complain about the misnamed "gun show loophole." Why is it misnamed? Because federally licensed firearms dealers must perform a background check to sell a gun no matter what the point of sale. If a dealer sells a gun at a gun show, then he has to run a background check. The "loophole," such as it is, is not specific to gun shows. It refers to the fact that one private individual can sell a firearm to another private individual without performing such a check.
Does this mean potentially dangerous people have another way to get guns without alerting the authorities? Sure—just as the Fourth Amendment gives them a "loophole" to avoid being searched by the police at whim. As A. Barton Hinkle explains, what big government enthusiasts call a loophole the rest of us call liberty.