Originally Posted by
txviking
But do airlines deliberately impose this requirement where the law does not require it?
Put it down to laziness. Trying to figure out the US visa system with immigrant, non-immigrant, and dual intent visas and then the multitude of LSR once in the US, and then having to program the data entry system for them is simply not worth the effort compared to splitting it in two as "citizen" and "everyone else". It sucks, but it's not likely to change any time soon.