I just deleted a pretty long reply, can't be bothered with the fine points. In the end I don't think they're relevant anyway. My personal stance is that I would not want to do business with a bank that instituted policies that I don't agree with. The hat issue is one example of one that I don't agree with.

As mentioned, I worked for a bank and I know the real and concrete steps we used to take for security and I personally know two people who were robbed in the typical one-man-one-note fashion. The hat theory is simply bullshit and anyone stupid enough to try robbing small amounts of money in this way will be stupid enough to do it regardless of policy and regardless of hat.