[grownseed]

I think your point is very valid, but my own experience (average white male) suggests that it might not necessarily be true. I used to have really long hair, which I would generally leave untied when travelling (mostly for comfort reasons). I started noticing that I would frequently get "random" pat-downs and searches despite not triggering the detectors. It never seemed to happen when my hair was tied back, so I decided to try it out over a number of flights, and fair enough, I would almost consistently get "randomly" searched with my hair untied, and not once was I "randomly" searched with my hair tied. Definitely not proof of anything, but it does indicate some kind of bias.