I don't want to open that can of worms again so I will just make this statement and not elaborate, as this was discussed to death.

I believe that there is a subtle difference between a "musician" and "someone who knows how to play an instrument". And this thread is kind of about where I believe that line is.

Funny that you mentioned the horns and "flat" instruments.

When I took up the sax I bought an alto. I took it home, played a note on the piano and found it on the sax. I did that with a sax fingering book open and though I knew about it being an Eb instrument I had to hear for myself that the note that showed fingering and called F# was the top three keys closed and the middle key on the bottom hand closed, that note in my brain was A. I learned my sax in concert key. Then someone handed me charts written in Eb and before I did the gig I literally had to write new charts transposed to concert key. I have been playing sax now for over 30 years and still know it in concert key. Why that stinks is that if you hand me a tenor or a soprano I have to think about every note sine it is a Bb instrument, and that same F# on the paper, a concert A on the alto, is now a concert E. Totally messes me up. And if I have to think when I play, I can't play. I am too busy thinking.