When your pet kills a mob all on its own you don't get credit whether you're on its threat table or not (I just tested this out to make sure it was still the case) you have to do at least a little bit of damage to it or you wont get anything from the kill.
EDIT: You still can't loot mobs only your pet damages but you CAN get the Lovely Charms. My bad!
Though the issue still remains that you will go AFK and get logged out eventually.