i'm tempted to argue for a 'forgive-system':
a teamkilled player automatically 'forgives' the teamkiller, unless he presses some button (like M) after death. if he does, the teamkiller loses 1 multiplier
or something along those lines
however, that's not at all gonna help against trolling spawn teamkillers and with all the rage going around in an average game of cRPG, i doubt the system would be used fairly.
also, using this system, you can easily jump in front of someone's swing / arrow / bolt and grief them with the 'forgive-system' by not 'forgiving' them...
so after thinking about it a bit i'm thinking it's probably not worth it... best to stick with having lots of admins and letting them hand out punishments