This suggestion is that you enter a list (like the muting list), select the players name, then select whether you wanna make a giant red or green circle appear over his head.
Why? Because for rageball it'd be extremely useful to be able to make a simple overview of players you trust with playing the ball to and "Dat asshole who went afk when carrying the ball", etc, basicly these markers would only serve as reminders for players about other players, not actually affect gameplay, however, it might make it less likely that otherwise good teamwork is ruined by someone passing the ball to a TDMr, who then loses the ball by charging at a random enemy and ends up causing his team to lose the x several times in a row.
I made more arguments for it in rageball server but I'm to lazy/tired to cite them, will add poll sometime tomorrow, 'night EU.