Getting metadata right is honestly an issue that has been there for a long time. ID3v2.3 or ID3v2.4 are basically what you have to work with. Many programs also use custom TXXX or DIV tags to embed whatever into. So even if you get it right in on prog it is a disaster in another.
ID3v2.4 fixes many of the issues. But very few progs use it or default to 2.3. Plus the way an album can be sliced and diced for metadata is truly breathtaking.
Then add into that some of these programs try to use some form of acoustic id to try to find where it belongs. Which does what you are talking about. So you resort to setting the file read only so the program will not mess with the tags.
Then on top of that many of the online sources can be in bad shape for bands or releases. AC/DC is most certainly not alternative. But it is tagged that way in some databases. So data quality goes all the way from 'someone spent a lot of time getting this right' to 'someone uploaded whatever was in their mp3 library and called it a day'. Also even the data printed on the pages that came with it may have spelling errors and differences in spelling for individual tracks and artists. Some artists have 3-4 different aliases which one do you put it under without messing everything up or leave it stand alone and you forget you even had it.
Also differing releases is a pain too. Some albums have 40+ releases. Which one do you actually have. Does it really matter?
