The grief lock system was better in Planetside 1. Planetside 2 seems to be aiming for the same system its just not compete yet.
Personally I don't feel friendly fire belongs in an action FPS like Planetside 2. Accidentally team killing is constant and unavoidable.
The only good thing about friendly fire is you can destroy friendly vehicles that are blocking your path or friendly troops blocking doorways if they are
AFK.
By any chance were you throwing grenades when you got weapon locked? There is a nasty bug at the moment with grenades bouncing/lagging/warping around when you throw them. I threw one down a staircase yesterday only for it to explode under my feet killing me and my squad mates