Right, I was on a Knife only server the other day, trying to get my badge :D however some people were using guns... I opted to fire if fired upon. Is that wrong? Anyway I ran over to a flag to cap it (it was a flag they shouldnt have capped anyway, going by server rules). As I neared the flag two opponents opened up from my left, so I laid down and returned fire with my Voss L-AR, killing them both. Of course the admin on the server musn't have realised they were firing at me, cos he banned me (even though one of those people who were shooting at me had killed 2 of my teammates with gunfire). They didn't get banned though. Was I wrong to use the "fire if fired upon" tactic?
Server admins can't watch everyone at the same time, in this case the admin may have thought you opened fire first.
My view on it is never retaliate to someone breaking the server rules by breaking them yourself, more often than not you'll get caught and not them. ;)