I agree with Chris--! You'd need to use good judgement--! For me, it would be the fact that I could spray if I really wanted too. I like the suggestion about heavily salted water-- that would be great-- no damage but a P.I.A.
a lot of my friends live around me-- any weekend I'll run into someone I know driving. I would die laughing if one of my friends called--
"Hey, Bob.. I saw you today-- You were behind me on Broadway!!"
"Yeah...uh... Did your moped spray something on my car?"
"I take the fifth..."