While I can't point to any post by a Sony dev that specifically states that afk killing is illegal, I can share what happened to a mage in our guild. He was working on his BiC aug and needed faction, parked himself and pet in the appropriate zone and went afk for the evening. By the time he got back...

Think an 85 shammy with pet hold could do it?

Who is the NPC for the Beza instances?