Please make it known in one of the stickied map editor FAQs that if you load a map ID, load an xml and then export it, the map gets exported onto the ID loaded earlier unless a reset is done.
I had always wondered what happens when that is done, and assumed that it takes 20 cheese and makes a new ID because I had no faith in the devs. It was a lesson learned the hard way.

Also, am I allowed to put new maps on old, rejected IDs?