A Question Regarding Bank Robberies
Scenario A: There is a bank robbery. The police surround the bank and the robbers take hostages. Now there is a messy, drawn out situation requiring hostage negotiators.
Scenario B: There is a bank robbery. The police don't surround the bank; instead they hide and wait for the bank robbers to leave the bank, letting them think they're going to get away, then they arrest them.
Question: Why, if it avoids a hostage situation, don't the police ever do scenario B?