Just to add a side issue to this whole discussion:
I found out the other day that it doesn’t actually delete the placeholder, it just hides it. Try this: in an obs. with a placeholder, enter some taxon. Now the placeholder appears gone. Then change your mind, and delete your ID. Now the placeholder is back!
So it should be technically feasible for the system to take the placeholder, and insert it as a comment before the ID that clobbered it.