Well that's what you get when you combine cash business with numbnuts gun control laws. If it happened in Arizona, I never heard of it. There were also constantly visibly armed guards outside, and I would assume the employees were packing heat, too, if I were a criminal. Of course, you could say the same about a lot of businesses.

Though of course the mob doesn't advertise their protection racket. Assuming they aren't running the MJ game in the first place.