I still, many years later, remember a guy who used to walk the ocean frontage in Venice, CA while whistling classical music, early in the day, not one of the more famed performers there who did performing for the crowds, just a guy. I suppose he was a ucla music student or teacher of the time. One of life's big pleasures to hear him. It never occurred to me to interrupt to ask/talk.
I never could whistle, which I could list among my lifetime failures.