Such instrument change is useful sometimes, for example when you intend a xylophone player to start playing the triangle in the middle of a piece. If this can happen in music notation, we cannot prohibit such changes even though there're problems with MIDI generation.
Comments
See my comments here:-
http://musescore.org/en/node/12725#comment-43103
Regards
Michael
Such instrument change is useful sometimes, for example when you intend a xylophone player to start playing the triangle in the middle of a piece. If this can happen in music notation, we cannot prohibit such changes even though there're problems with MIDI generation.