If I play MP3 file in Winamp 5.666, I can safely edit tags in it via Mp3tag- because MP3s are apparently loaded 100% to that player. Proof: I can move that file around / delete it, at no pop up window will show up; and unless the playback reaches the end of such tampered with file or I press STOP, I can replay such moved / deleted file without sweat
This however does not work for other formats- to my despair
More about locked files by means of playback: