Suggestion: Banning Toxic Players Before a Match.

Getting somebody who calls "jg only" in a ranked match is a terrible thing. Nobody wants to wait 20 minutes just to ban them. More often than not, someone has to dodge and ends up getting punished for something that wasn't their fault. Can't we just ban people for bad behavior before we have to go through with them? Some sort of [number of players]/5 call to ban them on the grounds of a specified offense like at the endgame screen and be able to save ourselves from a bad game?