It's unfortunate that (it seems) every single TK, regardless of circumstances, gets awarded with punishment online. I was being VERY forgiving at first, but after getting punished EVERY SINGLE TIME (again, regardless of circumstances) I have too, had to resort to the same, for the most part.
I get TK/Punished all the time for playing an engineer, and the idiot drivers are too stupid to see that *CERTAIN* exits to a base have been mined by me. ESPECIALLY when That base is undefended (a regular occurrence during a particular large round of whack-a-mole flag capture). I always leave at least one entrance open, perferably one that has view/access from base defense objects (machine guns/tow missle emplacements,ect so they can be basically defended by one, or maybe two soldiers) but they just spawn at the base, hop in the vehicle and floor it out any exit they choose and blow up, and then proceed to punish me for it.
About the only time I forgive is when I am repairing a vehicle and they move it. I try really hard to not get behind them to do it, but sometimes they are taking fire while I am trying to repair. So being behind is my only choise. And then they instinctively back up to get away and I get flattened.