A lot of people don't know this because they're used to blindly agreeing to terms and accepting them as "the truth," but clauses which are not legal cannot be e

A lot of people don't know this because they're used to blindly agreeing to terms and accepting them as "the truth," but clauses which are not legal cannot be enforced. If they deny boarding for just any random reason they choose, the airline accepts that they may be subject to legal penalties. Denying boarding is more than merely refusing a private service. It's effectively revoking freedom to travel. It can also be more than simply an inconvenience to miss a flight. Even when merely overbooking passengers through no malice at all, European airlines are required to pay significant fees to customers who must miss flights. This is true in the U.S. as well due to the precedent set after Nader v. Allegheny Airlines, 426 U.S. 290 (1976). Airlines attempt to offer vouchers, but you are entitled to cash payouts. I once made an actual profit from a trip to Europe because Lufthansa overbooked us and paid more per ticket in fees than the cost of my flights and hotels.