Exactly. Generally people know who are going to be the "terrorists" and who are the average Joes. Its pretty obvious that the person who is Muslim is going to be more apt to blow up a plane where a generic white guy drinking a coke isn't going to want to. Yeah, we can be fooled, but on just about every plot this has held true.
How on earth can anyone just "know" who is going to be the terrorist? What you are saying is that you are stereotyping them on what they look like, and if they look Middle Eastern they are a suspected terrorist, which is quite a dangerous mentality. That "generic white guy" could be having suicidal thoughts and think lighting a firecracker on a plane would be the best way to stir controversy, and because he has nothing to live for does it. Labelling people because of what they look like only leads to making them scapegoats, which ultimatley leads to hate crimes as people get 'revenge'(even though that Arab guy walking down the street hasn't done anything wrong).
There's no such thing as a free lunch. -- Milton Friendman
