I'd bet the man had been previously abusive to the kids provoking the act of vandalism.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I make-up my facts as I need them.

Even well disciplined bored Kids have been know to get out of hand once in a while.
Then there is what one Kid won't do several Kids will do. Group think often turns them into dummies.

If you took a Kid to a Buss stop and told Him to get on the next Buss that comes a long alone He or She would be asking all kinds of questions as to were the Buss is going and how He or She would be getting back.

If a bunch of Kids was at the Buss stop and one of the suggested that they all get on the next Buss there is a good chance they might do it.

This happened to Me. I was at the Laundromat by Myself early in the Morning and there was a I guess about a 7 or 8 year old Kid in the Parking Lot throwing Rocks at stuff.
I had been writing something for My English Class and had a bunch of Notebook Paper. I made 2 simple Paper Air Planes and went out in the Parking Lot an launched them. That caught the Kid interest. After showing Him how to fold to make a Plane I gave Him 5 sheets of Paper and let Him make His own and He stopped throwing the Rocks and just played with the Planes.

He likely was not a bad Kid but just a bored one with no direction.

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84 300D, 82 Volvo 244Gl Diesel

He should have videoed the punks and taken their parents to court for damages. I question the $40k damages figure -- I just bought a shortsale condo that was pretty beat. Renovation costs were more like $3k total (with my doing most of the work) including paint, plastering, a new countertop, some electrical and plumbing... How did two kids do that much damage in a short time?

And I bet they were "entitled" little brats who felt they should not have been chased off the property earlier. They trespassed before, and did it again, this time taking their boredom out on someone else's property.
Even good kids can do idiotic things out of boredom though. The best way I could think to handle this would be to make an insurance claim for the materials, and for the kid's punishment sentence them work with the homeowner to fix it up. At the end of it they will learn that actions have consequences and they might even pick up a skill they can use later in life.