I flew standby recently for a full flight and was given a boarding pass at the gate 15 minutes before departure (in the middle of boarding) because 1 passenger did not show. I was wondering what would have happened if the no show appeared right after I got my boarding pass? What about after the jetway door was closed? What about after the cabin door was closed? What about after the jetway was pulled back?
In other words at what point is a standby passenger "safe"?