Enforcing Bans on Players who quit matchmade games

This has happened to me countless times at the beginning of a Rumble match, and usually me and my other teammate are out for ourselves to win the game 3v2… Enforcing bans would be a great way to keep people in the game. This has also happened to me during a ranked 3v3 game and it cost me a placement game… 343 put something in place so these people are stopped.