The Sword ability can be used on players it has "Splash" damage. That can be used to kill innocent players, Also Mobs activate it i believe.
I don't think there is a way to fix this, unless there's some way to cancel splash damage if a mob is hit near a player.
Would it hurt a player if there is no PVP on? I can't see it doing that... So it would only happen in PVP arenas. Players in PVP arenas aren't really "innocent," right? o.o
Hmm, well splash potions dont work in wild right? Then i doubt this will if its in a no PVP zone so probably its fine as it is, from what ive seen
Please fix this... I was mining with a friend once and was killing a spider, so I activated Serraded Strikes. It started hurting him and he died and thought i killed him purposely and wouldn't talk to me for an hour -.-
