All very good responses.
Plus you'd have to be well financed for the full-body armor, the many bullets and the illegally obtained minigun. Add the weight of all that sh*t, it's just simpler to go in light and quick rather than carry around all that sh*t that slows you down and effectively kills you anyway.
Easier said than done, but i'm sure there's better ways. And yes, the trust factor would put you on shaky grounds too. A very well thought out plan, after 2-3 years or more, is far better than an all out war scene outside of a busy bank in the city/country with no real objective other than grab cash and worry about the rest when you get it.
The Town is a pretty good movie i have to say.
^ I like the "throw the paint on your helmet"... Bloody good suggestion