Sometimes you get lucky. I was carrying on a guitar (admittedly this was years ago) and the attendant was demanding that I check it which, having heard the horror stories, I was very reluctant to do. The captain asked, "What have you got in there?" Martin D-28, I replied. He said, "I'm a player myself. That's a nice guitar. Why don't you let me carry that up in the cockpit for you?" Handed it out to me at the end of the flight.