Heavy punishment for early afk trolls

I bet this is not the 1st time for players who encounter these types of trolls. Riot shout introduce a system where it will punish and ban a player who troll the game and leave the game early with severe consequences. I met one troll katarina player, whom got ganked twice and died twice just before 5 minutes mark and decided to troll by leaving the game very early. Thus making the entire game unplayable cos of that.