This is your first warning, next time please look into a situation much more carefully before resorting to a kick/ban. I understand that it sometimes gets really confusing in-game, but if your in any doubt about what is going on, just wait a bit, there is an extremely good chance that the person will continue to do what ever he was doing leaving you with no doubt in your action.
Do not ban for a first offense, if you kick the person and he immediately rejoins and starts Excessively RDM'ing (or w/e) again, then go ahead and feel free to ban him.
If I have to issue another warning, you will be added to the respected user blacklist for one month.
Just remember, have fun! it's what these servers are here for!