Windows Media Player has these settings about updating tags and "rearrange my music" that could cause folk to claim it corrupts content.
You make a good case for backups of such things.
Mp3 files on an external drive seemed to become unplayable after connecting the drive to a win 7 machine. the pc is not mine. a friend sent me some samples of the bad files and asked if i could play them or convert them to a playable form of some type. no luck at my end. the mp3 files were created on win 2000 and xp machines. the damage occured only after being attached to the win 7.