Top Team Killer so far is...
You have hit 25 friendly objects and killed 10 of them in addition to 0 enemy kills. Congrats, you've been banned.
One of the lovely things with slmod v7 is it has detailed stats. I did some searching through the file and made the choice to ban a few people. All in all it sort of revealing of the habits players have in MP. In one instance some guy used a CBU-97 to kill 5 friendly infantry.
I guess running with kill messages off and a mission with non-US friendly forces on the ground is bound to cause team kills.
People banned for stupidity: