U.S. football and the kneel down to end the half or game. That kind of stretches the definition of quitting but with the NFL's ridiculously long play clock teams can pretty much walk off the field with almost a minute left. Canadian rules are not quite as bad but it can still be done.
Moscow Red Army briefly walked off the ice during a game vs .Philadelphia in 1976 but returned to finish it.
https://en.wikipedia.org/wiki/1976_P...3Red_Army_game