Maybe every store should keep a couple of these behind the counter, and spray everyone in site when a flash mob attacks. You cannot do crowd control in a situation like this with lethal force.
http://www.sabrered.com/servlet/the-Frontiersman-Pepper-Spray-cln-Bear-Attack-Deterrent/Categories
http://www.guardian-self-defense.com/bear_spray_category.htm?gclid=CPSSx__2yrgCFadj7AodADIA3Q
Comments?
I will have to look into this. Looks promising.