Hmm.. this is a predicament and is hard to say what the right thing to do is. I'm leaning towards telling the parents of the kids but like you said the insurance covers it. I'm not justying what the children did but I'm sure we all did silly things we regret as children. Maybe they learnt their lesson but if you see them again I'd give them a warning or tell them you'll tell their parents next time.
If you can identify the shits, I would say you should do the right thing by notifying the authorities. Otherwise just mind your own business.
Good point. Can you identify them or know where they live?