PSA: Don't let your friends play on your account.

I literally played with someone who basically inted 9 times. He leaves base without buying any items whatsoever. This player claimed that he doesnt know how to play the game, levels up his abilities but then doesnt then chooses not to level up to six. Whether his claim is true or not doesnt change the fact that the account that he was on will sooner or later get banned for while. Then next thing I know, the person who owns the account will complain to riot that he didnt troll or do anything wrong and say that his friend played on the account. Like, dude, change your password or something. It'd be cool if there was a option to authenticate his log in or send an email to players that notifies whether you logged in to your account or not.