I don't believe the TSA, at the routine level, make distinction between domestic and not (unless you fit a racial profile). It's when things heat up that the problems begin. Being arrested in the UK as a citizen of the UK is not a big deal IMHO, a night in a cell is a bummer, but not the end of the world. In the US, on a visa, I have no idea what is and isn't being recorded about me, and a reasonable amount of paranoia is required.

As the OP said, the other aspect is that you are flying because you need to be somewhere and flight is the only option. This more heavily biases international travelers towards compliance, because they have a lot more to lose in time/money if they don't board their flight.