Theres plenty of articles out there about this topic.
http://www.salon.com/2012/04/08/u_s_filmmaker_repeatedly_det...
And they act the same way too, looking at you as if you were a criminal and asking you questions barking.
Of course they did break into my suit case and destroy my pad lock but hey ho, at least they left me a friendly note.
Anyway I think it's important that both sides of the coin are represented here, people are more likely to write about negative experiences in general.
^We were on honeymoon in Orlando which probably accounts for the generally positive reception :)
Based off of similar discussions I've had with other people on flights like this, a really good first approximation of the stopping time is "color of skin."