It explains itself. You finaly get enough people to start a match, satisfied with your 3 player FFA made up game that both players agreed to follow. Then suddenly, one of them starts spamming- asked them not too- ignored. And they also start breaking the rules of the made up game. What now? Either leave the game that finally got enough people to start, or stay when someone is annoying the heck out of you. Add the third option. Ingame kick. Please.
Problem with this is that it will be abused... like players being kicked just cause they're winning. Best option would make an in-game mute buttom and you can always kick the troll guy after the match is done.
Except in game mute already exist. >_> But anyways, yes. I believe that in game kicking may just end up being abused. Especially with low levels who are paranoid about people using rulers. I think it will just further make it difficult for people at high levels to even find games when they are constantly kicked from them. I personally don't see in game kicking as a good thing, and like Johan said you can always just kick players who misbehave afterwards, maybe mark them as people who you block on Steam in case they have the desire to change both avatar, and username to get around you kicking them later on.