For all practical purposes, this behavior is not new. What was actually new was when they started preventing multiple enrollments for Android last year or thereabouts. For many years, any enrollment of our Android devices which did not include a manual deletion of the old device from the console resulted in a new device record which could exist along with any number of previous enrollments of the same device.
To solve problems with billing and clutter buildup, we incorporated Kevin's suggestion. Firstly, we began relying more heavily on our separate inventory/assignment system to maintain history and related info. Secondly, we began using the AW/WS1 API to delete devices once we had archived (or deemed un-recoverable) all important data from the devices. The API calls included a loop to continue deleting devices by serial number until there are no matching search results, since the delete by alternate ID only deletes one matching device at a time. You could also use the IMEI or MAC address for these API calls with a minor adjustment to the call.
So, I'm not personally concerned or worried, since we've been effectively dealing with this type of behavior for years.
