When you try to save tags to read-only files, MusicBee will give a warning on that, and will allow to write then anyway. (nice)
But when doing volume analysis on read-only files, MB will just say 'analysis completed', without any mentioning that the tags were actually not written to these files at all.
So you'll end up with files without replaygain tags, while you are convinced you have processed them.
A warning, or an override would be very useful here.