There is a basic difference between any kind of (real) edit to the music
(changing notes etc.), which affects scores and parts, and switching the
concert pitch state, which doesn't actually change the music and therefore
only affects the score or the part, whose concert pitch state is changed.
Since however, a concert pitch change is done by transposing,
undoChangePitch() is finally called and will apply the changes to the linked
elements in any case.
Some flag in the Score object (Score::changingConcertPitch), indicating that a
concert pitch state change is going on, could tell undoChangePitch() not to
run through the linked elements. This migt also be useful for key signature
changes, which are currently not copied to linked staves.