I used to have this happen to me, but only in the largest and laggiest of ZERG fights. Then I got more experienced and it simply doesn't happen anymore. Most of the suggestions I would make are already posted above me, but this can certainly be avoided by simply playing more carefully when you get that first FF warning. One thing that I think needs changing is the way that vehicle FF is calculated, especially when it comes to bumping into friendlies. I frequently try to play CqC canister harasser mixed in with groups of infantry. I can literally get weapons locked for people bumping into me. I also get weapons locked in these scenarios when the game thinks my harasser is sliding/gliding/twitching/glitching or whatever you want to call that magical sensation of moving while sitting in a stationary vehicle. I also get the warnings for driving near people without ever actually killing anyone. Harasser wheels seem to suck enemies under them even when you aren't moving.