Only time I got a double bump was 4/2/04. Five of us going DL, ATL - HNL.

They only needed four volunteers, so one of us had to go as scheduled. We had planned for this contingency with the folks meeting us in Hilo and the folks picking us up. So the four of us wandered over to our new gate, got bumped again. Got $400/person/bump.

The next day our flight was oversold again but they only offered same $400/person and couldn't get us out until the next day. We decided not to take it. We were sitting in our seats on the plane, they asked again at $600. But we decided it was time to start our vacation.