Clear regulation stating that a passenger may not be forced to leave for any but safety reasons once they're seated, rather than leaving it up to a contract, an

Clear regulation stating that a passenger may not be forced to leave for any but safety reasons once they're seated, rather than leaving it up to a contract, and providing sufficient funding to whichever organization enforces that regulation? One of the more promising candidates for the cause of such great expense for various services and projects in the US versus other (generally more-regulation-heavy and more-worker-friendly) OECD states, as recently discussed on here (following a Slate Star Codex post on the topic) is the risk/expense of relying so heavily on contracts and lawsuits to sort out this kind of stuff on a case-by-case basis rather than simply stating that things will be a certain way through regulation, removing (or at least greatly reducing) the uncertainty.