It turns out that Chris Cooper -- the artist who created that sticker that a New Mexico D.A. says is obscene-as-to-minors -- is a regular reader of this blog (which I hadn't known). He e-mails:
As the artist who created the artwork in question, I'm more than a little interested in this case, and I'm very worried that the person in question might get thrown in the klink for having a sticker on his car. That just doesn't seem like something that should happen in the USA. I hope that your analysis of the statute is one that is shared by the court.
An unsurprising reaction, of course, but I figured that since I had something straight from the horse's mouth, I'd pass it along.