David Levine wrote:"The idea in a session, IMO, is not to confuse or otherwise keep folks on their toes, but to play things communally."
If you're with sympathetic people and musicians you feel comfortable with, you can do anything with a wink and a smile. It's a give and take, always. I love it when somebody I've been playing with for years introduces a new wrinkle. What I don't like is when somebody I don't know is showing of just to impress.
Agreed. An odd deviation here and there - talking flute and keeping my own quirks private - is never a bad idea, especially on a tune we're otherwise bored to tears with. And playing with people you're comfortable with, and like, never hurts.
Sometimes tunes are just learned differently, place to place. I ran into that recently at a new (for me) session in the second part of Sheehan's - an old chestnut tune I've played for years. They all went into the tune, and I jumped in. In the second part, they dipped into a minor key. I thought the guitar player hit an odd (read, wrong) chord, but next time 'round, I realized the fiddlers, too, had dipped into the same, aformentioned and infamous F nat, and , in what was/is a major key tune. It was easy enough to half-hole the note and keep going, but it took me by surprise. Still, it was their session, not mine.