profile the minority/foreign/likely suspects who don't fit in and might actually have an ideological reason to terrorize us, not average joe
the hand/finger thing is probably because lots of freelance "cooks" and "operative" burn themselves or blow off/cripple fingers when they get sloppy. I've seen ieds and they are pretty volatile at times. when they wire them up the things go off sometimes- ask anyone you know that's been in the iraqi streets and they'll tell you about a hajji that got sloppy and left a sloppy mess on the streets at night (marines get trash bags and clean them up)
though here in america that kind of profiling is not necessary, not the hand thing I mean. blue collar country guys who work for a living get dinged up and I DO think it's a wedge to get deeper in the profiling. I have to wonder what about the muslims, why aren't THEY on the profile?