Penalty for leaving players

Since this game has a big quitter problem right now, the introduction of an automattic, escalating penalty system is a must; the game being F2P does not hinder this at all, League of Legends is also F2P and has also a penalty system in place. And since some champions and skins are behind a grind/paywall, it will be quite useful as well.

It should start with a 10 minute block for joining the next match, then 30 minutes, 1 hour, 4 hours, 1 day, 3 days or something like that; including a XP penalty as well, which only goes away after playing X games without leaving.