Nobody seriously believes for one second that the people in the video are remotely representitive of Americans, right?
All we have seen is the power of TV to present a bias, in this case for the purpose of poking a bit of fun at the more ignorant minority cross section of the population.
No doubt the guy asked the same questions of countless other people who probably just shook their heads and walked away in disbelief.
Although this was clearly slanted, consider the effectiveness of the same techniques used by the media in general. Next time you see a nice library footage clip of some extremists chanting 'death to america' etc. as part of the latest special report / poll / terrorist headline, ask yourself if this is really representitive of the billion or more muslims in the world.
Anyway, I don't think devout muslims really need to carry special ID. It's not as if they are difficult to identify. Hint: beards, caps, robes, loitering around mosques... ;-)
