Survivor (American TV series)
In many seasons, the tribes have been switched before the merge. The members of each tribe are swapped around. Sometimes the tribes are switched by doing a random shuffle to a schoolyard pick, where two players ("captains") would start picking players for their tribe. There has also been a Tribe Switch which is done by allowing players to join the other tribe. This process usually defeats many early alliances and strategies, and can cost a player the game early, or save them from being voted off early.