Why Riot just doesn't permanently ban anyone that trolls a game? I mean anyone that starts feeding on purpose, goes to base and stays there until game ends, like really obvious trolls that ruin the game.
This are actions that are easly controlled, not like talking crap in the chat. No one says "I can't control myself sometimes and start feeding on purpose because I am so mad". This kind of people do it willingly to ruin others games for fun not because they are just tiled.
This should call for an immediate perma ban. If Riot did this you can bet you would never see anyone anymore running down turrents and leting themselves getting killed or stay in base until game is over.