Don Firth:
(in response to my posting:
". . . the composer sets in stone every note that is to be played, and the orchestra plays no part in that creative process.")
"This seems to be a fairly common misconception held by folk music (and sometimes jazz) enthusiasts."

I totally agree with almost everything you wrote following that. But as well as being a folk music enthusiast and performer, I also spent the first 12 years of my musical life playing classical music, so I'm not subscribing to a common misconception.

The composer mostly DOES specify the notes that are to be played.
I said "the orchestra plays no part in THAT creative process" (note emphasis), meaning choosing what notes to play, harmonies and instrumentation. Within that structure I agree that the player (or for an orchestra, the conductor too) has a huge amount of creative license for tempo, phrasing, dynamics, timing and whatever else goes into making a page full of dots into a performance. There is also the choice of how big an orchestra to use. But with a few exceptions, the players do not routinely rewrite or rearrange the music and this remains a distinction between classical and folk performance.

Actually, Bellowhead are interestingly borderline in this respect. Paul Sartin (who of course has a classical music background) wrote out parts for each instrument in the band, and for many months after the band started gigging, the brass section even had sheet music with them on the stage. So it wouldn't be impossible for another band to play Bellowhead's arrangements as somebody imagined earlier in the thread.
But a folk band doing that would also have no qualms about changing the arrangement to suit their taste or instruments.

I still think that most orchestral musicians feel uncomfortable about straying from exactly what's written. Anecdotal example: I once played cello in an amateur performance of Handel's Messiah. There was one other cellist and no double bass. I don't remember if Handel wrote a bass part or whether the same part was supplied (as was common in his time) for both instruments, but I took it upon myself to play everything I could an octave lower so it would be at the equivalent pitch of a bass. It made perfect musical sense to me, but it had the girl playing 1st cello in fits of giggles because it seemed such a strange thing to do.

Anahata