After some searching (Google: PRIV Frame ID3 Tag) and some forum reading, I came up with this:
Mp3Tag
questions the utility of editing the PRIV fields since the fields only binary data
Moodmixer allows you to delete the PRIV fields
ID3 Raw Tag Viewer does too
(Both need .Net Framework 2.0)
In my 5 minutes with each, I like Raw Tag Viewer better. I've made edits to two songs with the Zune software open. Apparently one song was not in my library before. After using Raw Tag Viewer, Zune software recognized that song (good sign...). Another song was in already in my collection, but I removed the PRIV tag anyways. With this song, Raw Tag Viewer spit out an error and wouldn't remove the tags, but I opened the same file in Moodmixer and it got the job done. (Use both for a tag team maybe?) It looks like there's two PRIV tags and sometimes, they're not sequential in the tag listings. To be safe I'd remove both.
I have yet to sync, and I would guess that the software
will re-ID a song as it syncs it, hopefully its different. However, something leads me to also believe that these ZuneMediaID's are based on other metadata in the ID3 v2.3 tag, similar to what a unique hardwareID is to a computer as opposed to a sequentially assigned number. If I change enough of the metadata the song is considered different, not the song being considered different becasue of the order in which it's metadata was processed by the software. But hey, I still have to song hunt and tag edit...
Zune MVP
Contributor, http://www.insidethecircle.net