RE: What are were these kids thinking?
Last I knew it's also illegal for them to have a handgun unless they've got a reason to or are under adult supervison, and I'm not believing they'll get off on "I'm hunting", or "I'm target practicing" at night.
I would report them, and then if you see them, I'd tail them and call the cops on my cell (from a safe distance). I almost always have a gun with me as well, so if they wanted to MAKE ME RETALIATE, I'd be obliged to do so. I've got a feeling I'm a little more skilled with my arm than the punk kids, but I'd largely try to avoid such a situation.