Your Walmart scenario is very possible, and I would hate to see the widespread hysteria it would cause.
Hysteria, no. Revenge pogrom, yes. Many people underestimate "mob mentality". This was the reason that the media covered up the DC sniper shootings. The local law enforcement knew that it could cause a backlash. The simmering hate and resentment against all things Islamic is at a full boil. Check out the White House Iftar Dinner thread, if it is still around.
DANG!!! I just purchased a new vacuum cleaner at WalMart. Guess I better return it before the towelheads strike!!