I'm level 87 it makes no difference what level you are. I play CTF exclusively at the moment and I'm CSR 16. I play with my friends whenever possible as they're quite skilled but sometimes we'll be a player down and guaranteed he will betray and p*ss everybody off. I can see the need for friendly fire as otherwise people would just throw grenades into a melee fight or sticky grenades on a teammates back and have them run into enemies, but maybe it should take shields down and not kill teammates, I don't know. Either way is better than the abortion that is the game right now. The system should recognize multple betrayals and ban.
Heck, their boosting detection system is top notch! I boosted like 20 kills for the assassination armor and got a 24 hour ban. Yeah, I deserved it, but if they put half their effort into the real issues with the game instead of a few people getting new armor it would be fixed by now.