You need an Admin password to use Backup Restore. However, if the evil-doer sets up a dummy practice, they can enter the dummy practice's Admin code to overwrite the dummy database with your .enc file. Then they can sign in with their own password. If they are provider level or know the Admin password of your practice, they have full access.
That's why Bert recommends password protecting the main computer or server, and not saving backups on a client computer.
