"Watch out! He's got a fetish for car horns!"

I was helping another officer with a warrant arrest on a guy who was 6' 5" and 260 lbs. He was a big guy. As we're doing the deed this young man comes riding by on a bike. He stops and ask if everything is okay. Part of me understands he's just curious. The other part of me is annoyed slightly. I tell him it's all good and to move on. He goes to the end of the street and watches us. Okay, fine as long as he stays away. One officer tells the lady officer with us that her boyfriend is here. She gets irritated. Ah, clearly another way to taunt her. She takes herself a little too seriously sometimes. They tell me the guy's name is Chris and he's autistic. He's in his early 20s. He has a fascination for the officers in that area, but especially the lady. I look at her and say "I think you two would make a nice couple!" She shoots me that 'go to hell' look. They tell me "watch out he's got a fetish for car horns!" Apparently he will ride around and go into peoples' cars and honk their horns. Well, aside from annoying can't see how that is illegal. He doesn't steal anything, he just honks horns. I get in my car to leave and he comes to me. He's never seen me out there before (which is good). He shakes my hand then suddenly starts honking the horn. Oh lord!