We connect external air to all our nightstops, leave the aircraft on ground service, and close the door.
One bright captain last winter pressed the ditching button before leaving the aircraft, without telling or asking anyone. When I had finished the checks, I left, and then the cleaners closed the door.
In the morning, the crew walk down the jetty. The dispatcher says that she can't open the door. The captain sees that the red light is flashing. That can't be right, he says, let me do it. The first officer caught him as the door propelled him across the jetty.