Throwing rocks at cars is stupid

I was headed to the grocery store, milk run, just after the elemetary school kids in the first time track got out. My kids are in second track so they still had about 45 minutes of school left. I was a few blocks from the school and I noticed two girls throw things at the car in front of me. It looked like rocks. I made sure to glare at them as I was driving past so they'd be intimidated and not throw rocks at my car -- but they did! The nerve! So I did something very un-Paige like. I stopped the car.

The girls took off running in different directions. Then, since I was in the middle of the street I drove forward and pulled up to the curb. It took me a few seconds to get out of the car since the handle is broken and I have to roll down the window to open my door. One girl was hiding behind a picket fence, completely visible. The other girl had run in the opposite direction from the way I was driving and then back-tracked to her friend and then was heading back again, probably in the direction of her house, when I caught up to her.

I stayed 10 feet away then I delivered my "speech."

me: "Don't do that."
girl: "Don't do what?"
me: "Throw rocks at cars. Someone could get hurt or you could do a lot of damage. It's a stupid thing to do so don't do it again."
girl: nodding
me: (as I'm turning to walk away) "and tell your friend since she's over there hiding and missed getting yelled at."

I didn't yell, just used my sternest, loud voice. And as I was about to say the word stupid I wondered if I should phrase it a different way but then decided that stupid coming from a grown-up had the effect that I hoped to convey.

I wasn't worried about my car. They were little rocks and our car, though new to us since the summer, is not at all new. I just couldn't let those girls stand there on the sidewalk and throw rocks at cars. If they didn't even have the sense to at least hide while throwing things, they looked like they were in fourth grade, then they needed to be told.

I'm not sure how I feel about it now. I'm not sorry I said something but I could have been less mean sounding. But then would they have listened? It isn't really something to laugh off in a disrespectful kid way. And maybe someday, that girl will be tempted to do something rotten and she'll remember the crazy lady jumped out of the car and told her not to do stupid things. That's what I'm hoping she remembers anyway.

ps - my kids were shocked that I stopped, kind of embarrassed I think. But then they thought I should have told the principal about it or their parents. Hopefully this will keep them from doing stupid things too. At least some stupid things.