Not necessarily, if a ghost-kill occurs, it will be allowed due to the fact that nobody can control it. It's unfair in some cases because I particularly knew a guy who ghosted almost every other second and we couldn't kill him or it would be considered ghost killing.
By the way, what clans are you talking about because I hang around most of the clans in my Leaderboards and they know that ghost-killing is fair game.
New Rule Implemented
19. Ghost killing is allowed due to the fact that it's uncontrollable and mainly the player's fault.