On the last few international trips I've taken, the checkin staff has wanted to see my papers for entering the US. I work/live in the US legally on a work permit (not a visa), so I posess a Canadian passport and no GC. The checkin staff always seem bewildered that one can work via a work permit and I always seem to get delayed for awhile while the staff chats amongst themselves about whether or not I can checkin/board. The work permit itself is just a stamp in my passport (rather than a visa sticker)... which creates even more confusion. There's no possible way that people in other nations know what all the rules are for the US, so why do they have to check them? Besides, even if I was just visiting the US, I still wouldn't need a visa.... but I wouldn't really expect everyone to know that either. Does anyone know why this doc check exists? I've been lucky so far that I have convinced the staff that my documents are in order, but I'm a little worried that I won't always be so lucky.