I have my own L4D server, and i just experianced people (survivors) jumping off buildings to suicide kill all his teammates and then quit or something like that too many times and i just grew too tired of it now so i got this idea that you could maybe create a plugin that allow admins to log a player on the server and if a player leaves a little box appears and asks if the admin wants to log the player and then there comes some reasons that you can choose then the next time he is on the server the plugin with notify an admin / admins ( if there is one on the server ) about the player and the reason he got logged. Then the admin can either choose to kick or ban the player.
I imagined something like a little box popup in the left side of the screen.