Players that add you after game.

I just finished a game of ARAM as Jhin, nobody was saying a word until the end of the game when the enemy gragas says "Jhin needs a nerf" then the game ends. Alright time to queue up again, I get a friend request, I get friend requests all the time from people I don't know but I typically accept them just to see what they say, or it's a friends friend. It's the gragas from last game, he tells me "Get raped to death" then immediately deletes me. I have a screenshot of it. Don't think it's right that people can straight up verbal abuse you out of game to try to get around the rules.