and give warning before banning, I'm sure you are supposed to do that anyway
There's no admin warnings for team hits or kills, it's common sense that you're not supposed to attack your teammates.
(Don't counter-tk/counter-th either, that's just as bad. Click
CTRL + M, yell in admin chat (click
I) and report it in the forum.)
Admin warnings are given for leechers, delayers, minor offenses etc, things people might not know is a rule.
If we were to give warnings out to people who's team-hitting/killing it would be abused beyond belief.
Also; whether or not the one you team hit/kill "says OK" or whatever doesn't change anything, the fact that you are team hitting or killing means you're hurting your own team, and therefore admins will and should take action.