What's the point of holding them with you anyway? Instead of kicking them out, then get a replacement and continue your duty, you'd rather play with one man short and then kick them before the last boss? It'll be your loss instead of the guy sitting at the entrance and probably playing Facebook or something. You think you're punishing them by not kicking them and forcing them to waste their time but they actually don't care. The best solution is kicking them out and move on.

You don't want to waste your kick quota? You SHOULD spend your quota on someone like that. If you don't want to kick an azzhole sitting on the ground doing nothing then who do you want to kick? It's not like you'll meet an ultimate troll every two hours while nobody has a kick quota left.