Well there's nothing stoping you from using another node. Just means that in the editing history it will give credit to whoever you used. Also if their me node being correct is important to either of you then don't add the tree to your account until the needed node is added then share the tree again, but using the correct node.
If proper crediting in the edit history is important to either of you then just add the person's node with an incorect conection (as a sibling for example) then edit in what ever the most imideate correct conection to the tree they have and remove the incorect conection from their node.
