Hmmm, still ver' strange to me. I CAN play in any key, but don't much like things with more than 3 sharps or flats. Neither of our banjo players re tune to play in any key.........both they and the guitars sometimes use a capo. Sometimes I can relearn a tune in a different key, but fiddles commonly run out of notes if the tune isn't in the 'correct'key. Example--we can play Whiskey Before Breakfast in D but not in G. Run out of notes on the bottom end. Also, changing keys on a fiddle means a whole new set of fingerings. I originally learned Gal I Left Behind in Eb--then found out the rest of the world plays it in G.