On the 17th of July, Occupy DC blockaded and shut down the Bank of America branch closest to McPherson Square. Occupy marched in carrying furniture which was to be used to occupy the branch, but the bank expected the occupation and locked their doors in advance.
Occupiers then entered 1090 Vermont Ave itself, trying for the back doors of the bank branch, but they too were locked. At that point, protesters returned to the front door, blocking it with a sit-down blockade for a while. The door remained locked, doing the job of the sit-in whether protesters were blocking it or not!
Customers were effectively diverted to the ATM, where Occupiers asked them to withdraw all their money and move it to a credit union. For perhaps an hour, not only were the front doors shut, but the back bank doors inside the main building were also shut, with building security only admitting people with business upstairs. Eventually security began escorting what few customers the band could still attract in through the side doors of the main building, but the front door remained locked until the bank closed at 5PM.
Only then did Occupy leave.