Files that have ratings in their tags show their ratings as though I manually rated them in MusicBee, getting mixed in with them all.
Another, same-y opinion to frankz.
And technical question - how is any program suposed to differentiate between ratings from elsewhere, and from within musicbee ? (since both write to the same metadata field as per the file convention).
Unless you (as the only one who knows which rating is which) mark them in some way, there is no way for MusicBee to differentiate these... and I doubt there's a technical angle under which this could be done. Unless you'd force MusicBee to write its' own ratings elsewhere. But - in that case I'd also agree with frankz:
"Some things are best handled by the user taking hold of his or her own data management" statament.
And you best path would be to shove the rating you do not want to see in musicbee, but still keep, in a different custom metadata field, and musicbee can write to the official ratings field...