C4 with enemy friendly fire

During the beta, I had put a lot of c4 on a tank but was then killed by an enemy explosive. This blew up my c4 and didn't seem to damage the tank. It's the c4 damage from the person who planted it, or from the person who destroyed it? Understand it would be hard to balance as it causes friendly fire, and would be easier to manage with friendly. But the person who planted c4 should always be given the rights to the damage.