OK, so I swear I didn't do this totally based on this thread... I was one of the lead heavies working hard at peek-a-boo around the corner, and half-way through it I try to back up to not get shot... but hear that grinding noise that means some asswipe is behind me when everyone else was doing just fine firing in formation and taking turns.
Turns out is isn't even one of the original forward attackers... it's some T-34 (Russian) that came out of nowhere just because I guess he thought I was doing well at that front.
And... he didn't immediately move (somehow completely ignoring the tanks lined up parallel to each other for firing and backing up). It took a while for my Amrican T34 to reload, but I gave him one. But... then... it was either my continual trying to back up, or maybe he had an engine fire from my prior shot... somehow he died some time after me shooting him, and I got the call that that was a friendly (or whatever the message is these days).
Now we were winning 4 to 0 at this point, so now it's 4 to 1 (me giving that team their only kill that far in, lol). I'm sure they, and everyone, noticed, but the battle was still on, so I kept at it. My in-game score was 1 just before that point, but now it read zero to account for the -1 (negative one) I incurred.
But then hard work paid off and I eventually showed three kills at the end of the game, even though I really had four ... no, actually five if you count my teammate, lol.
I was wondering how bad I'd get my dick slapped for the team kill, but it wasn't too bad. SInce this is the current theme of this thread, I figured you guys would want to see the monetary / XP effect of a total kill of a tier ... whatever a T-34 is ... and I didn't turn blue.
I may develop a theory that an early team sacrifice to the gods of war is the way to earn awesome wins.