Interestingly I just attempted to remove some music.
My idea was to have the music on the menu screen but no music when at sea, except when killed.
So first I took all sections besides [defeat] and [intro] and set Tracks=0
No joy, still got the music and when I loaded a save from within a loaded save, it crashed.
So, I made an ogg file that was 1 minute long and silent. Changed all the sections to Tracks=1 and Track1=silence.ogg
Again, it acted like I didn't change a thing when loading a save game.
At this point I noticed that the radio being on shuts off the music so I stopped trying.