Reminds me of an event that someone told me a few years ago. He was flying a Piper Super Cub across the nullarbour ( hope I've spelt it correctly). This aircraft was used in WA for shark spotting and was fitted with a siren underneath, he was coming up behind a guy on a motorbike so he descended fairly low and when he was just above and behind him, he gave him a blast on the siren. The guy looked behind him down the road, probably thought the police were on his tail, but he saw nothing and continued on his way so our pilot gave him another siren blast but this time he spotted our aviator so he gave him the two fingers sign, opened the throttle and disappeared into the distance, our pilot never caught him up. True story.
Alan.