When leaving fly-ins and whatnot, often cameras are rolling and there's temptation for a hold-my-beer-and-watch-this departure. And that's exactly why I just depart very smoothly into the sunset and they can film that. As others said, if you do say something to a nitwit, they will just flat out deny it. Report to authorities and they can do nothing without video proof, and even then probably nuthin. Years later when they change occupation and become an 'aircraft parts distributor' (all over the field), everyone comes out of the woodwork and and says "yep, we all knew it was only a matter of time and place."