|Usually, on Siege Perilous, musical instruments wear out.
While trying to use the Musicial skill gain tactic on wandering healer (lock down entice), I noticed a message saying my "sandstone arch" was destroyed. This is a normal error I have seen before when using my instrument. The instrument is usually destroyed though (normally I just keep playing the instrument until it breaks. I think it even broke once when I tried to use provocation.)
This time I was using a "tamborine". It did not vanish from my pack. I then tried Peacemaking, and again it was not consumed. I haven't had the guts to try using it just to "play" or provoke with.
If you plan to try to GM Musicianship on Siege, you only need 1 instrument and just keep Enticing an NPC.