Isn't dropping a bunch of money on a group of wanting persons going to incite a riot? Or at least some pushing/shoving/fighting? What's stopping non-homeless from hanging out and grabbing cash, too? Great idea, but I think the execution of it needs a little work.
I think you overestimate the greediness of homeless people and underestimate the amount of planning that has gone into this event. I think a riot is far more likely to occur dropping $1 bills on Wall St. The area this drop will be taking place is highly populated with transients and it is very unlikely that there will be anyone nearby who isn't in need of charity.