I was actually caught off guard about this during development, too. That’s why my MAAS test environment post suggests creating a container to host the hypervisor.
Another idea I remember we discussed was using a “prefix filter”, such as how Add Hardware > Chassis works, so that MAAS only manages and creates VMs with a specified string prefixed to the VM name.
If we should clarify this in the UI, we should open a new bug for that, since the old bug was already decided on as a Won't Fix.
On the other hand, if there is another a way to solve this in a way that’s simple for users and doesn’t cause excessive complexity/maintenance in the MAAS code, let’s discuss. How would you like to see this fixed, ideally?