Policy says to give the criminal what they want and get them out of the place with no resistance as quickly as possible. I'm not sure the new No Carry policy has much to do with them fearing open carry criminals. I would bet it does have something to do with having armed and unpredictable Jo Citizen in the mix during a bank robbery.
They'd look at it as a liability. There was a case last year where a customer tackled a bank robber and ended up getting a couple people shot. They then turned around and sued the customer.