Some years ago, I saw a movie on the local TV-net about the World War II,
in which a barrel organ (or actually better: a "draaiorgel") played quite
a "big rolle."  I believe a part of the title of the movie is "Amsterdam",
but I don't know if it was an English or American movie.  The organ was
owned by H. Gossling (a famous Dutch renter of organs) and in the movie
it was used as a shield and a kind of alarm-signal.

Hope this helps, Bjorn Isebaert