As I understand it, tagging files with Musicbrainz will enable my ratings to survive when I rename or move the files (or both) because the files are uniquely identified by the Musicbrainz IDs rather than location and filename.

First of all, is my understanding correct? And if so then would the ratings survive being moved/renamed in any circumstance or would I require a full rescan followed by a restoration of the ratings from a backup file? I ask because my few tests of this have resulted in my rating being lost...but I haven't tried the complete rescan yet.