In community orchestras I've played in, and in a couple professional ones too, some musicians do a thing that drives me nuts (though, really, nuts is a short walk for me). It's this, and I'll phrase it as a desperate plea:
When you're on stage warming up or otherwise in a place where the audience can hear you, for the love of God, do not practice licks, phrases, excerpts or any part of what you will be performing that night!
First, it just sounds terribly unprofessional. It also sounds like you suck. I mean, if moments before the performance you still have to practice your part, you clearly can't play it well enough and shouldn't be sitting in that chair. Practicing in front of the audience portions of what you'll be performing for them a few moments later is terribly bad form if for no other reason than you're pre-performing and taking a little of the magic away from the gig by virtue of the audience hearing it out of context before experiencing the piece.
I complained about it in a couple groups where I saw that happening and was greeted with disagreement ("Oh, it's fine. There's nothing wrong with it. We do that all the time.") or blank stares of incomprehension like...

I thought it was a well-known and universally accepted rule that it's very bad form and highly unprofessional to practice your part during warmups before a performance, when the audience can hear you.
Am I wrong?