I am just getting started ripping and tagging for slimsever. The slimserver WIKI warned that it is possible that Flac files contain ID3 tags, in which case serious problems can ensue.
A thread on this site (/t/2901/1 contradicts that warning. Florian states that Flac files cannot contain ID3 tags, and for that reason MP3Tag options for removing tags do not allow for deleting ID3 tags but not og Vorbis tags.
I brought up this conflict on the slimserver forum (http://forums.slimdevices.com/showthread.php?t=30430) and experienced users maintain that flac files can get corrupted with ID3 tags inserted by badly behaved programs.
Being a non-technical newbie to all of this, I do not know who is right or wrong. But I would suggest that if the slimserver community techies are correct, then MP3tag should include an option for finding and selectively deleting ID3 tags from flac files.
I will follow up that suggestion with a question: Can MP3Tag as currently configured detect ID3 tags in flac files and warn of that fact?