I've loved killing teammates in the pregame period before the game starts, more so in the beta when everyone would actually die... but the new "invincible" system doesn't always seem to be applied.
Occasionally teammates can still be killed, and rarer still is that I'll be giving a strike for a team kill as if it were in normal play period. That itself wouldn't matter as I have never been able to get to the 3 TK limit for a kick, but since release the damage reflection system will carryover into normal play.
For enjoying the ritualistic fratricide of pregame shenanigans I am occasionally slapped with full damage reflection before the game even starts, lasting the game all three rounds if it so happens to take that long.
My very low opinion of the damage reflection system aside, this is clearly an unintentional bug that only occurs about 10% of the time. This is also during co-op play only, in case that matters.