Upvote:3
Be honest, do you look like a bum?
I got singled out once, but not really. I was just the only non-EU citizen on an incoming flight. Everyone else was just waved through and I think they were just annoyed that had to do the full procedure for just one pax.
Upvote:5
It can be random, it can be being American, it can be your look, it can be your attitude. Often, the way you answer the first question defines how picky they get, but not always.
There is no hard rule; although they get trained for certain signs, each officer has his own way to pick out people he thinks need further questioning.