Actually this question doesn't surprise me at all.
Three years ago my american cousin flew over here without the appropriate paperwork and when questioned at Heathrow she said she had come over to work but had no job lined up, she was then horrified to be detained at the airport and threatened with deportation. It showed complete ignorance on her part, and an arrogance to assume that she was free to go where she pleased whilst accepting that the need for green cards and visa in America was ok.
Makes you wonder!
also on a recent flight from the US to Ireland I sat beside an American lady, we got into conversation and she actually asked me 'so where exactly is Ireland then?'.