is it illegal?

I went out to get the newspaper saturday morning, walking by my car, I noticed there was a giant, and I mean really big,(bigger 'n dallas) phallus drawn in the dirt on the side of my car. At first, I was really freaked out, I mean eeeuuu. Then I remembered i'd been to a bar the night before to see a blues band and so rather than someone creeping around in my driveway drawing on my car, it was more than likely some of the young punks that were out in the parking lot expressing themselves. And for sure they got a powerful point across. Nothing says "wash me" like a giant penis on the drivers side door! It still occurred to me to call the sheriff. (ok I'm in the city limits so I'd really call the police, but it sounds more western to call the "sheriff".) But then I'm wondering is it illegal to draw in the dirt on a persons car? It didn't scratch the paint, a wet rag removes it, and yet, it's objectionable material. Or is that a matter of taste really? I wanted to call the police at least to get a humorous posting in the police blotter of the newspaper. In this town, this topic could start quite a local controversy along the lines of "is it art?". In the end I washed it off with a little 409. I noticed then it was signed, the initials were tucked quietly around the top of my tail light.
The photo is of a necklace I made recently. It says "bless your heart". I'm hopelessly bad at taking photos.... but anyway, I say "bless your heart" to the little burgeoning artist who graced my car with his expression of bad taste.