People who demand a position that has been called or threat with trolling/feeding.

This is a problem that must stop. I am sick and tired of seeing this happen in games. It usually seems to happen to me. I will call a lane pregame and some idiot will come in late and demand that lane or they'll feed/troll. This is nonsense. Then in game they go that lane and ask the other team to report the player who called the lane first and it becomes a lose lose situation. I am tired of these. I want riot to implement a system that can stop this. Either a pregame role pick. So you'd pick top lane, bot, jungle, adc, support, what have you and then the game will find a group of players that fill the rest of the roll. Or would like to see riot upgrade the report system so that pregame trolls can be stopped before the game begins. A vote to kick someone off the team for example.