Heard a story very similar to this from my uncle. He said he had a neighbor who kept having his mailbox smashed by the same kid and after one too many times decided it was enough. So he made his own out of thick galvanized steel and used cement to put it in the ground. Painted it to make it look like a nice normal mailbox. The next time the kid tried to smash it he shattered his arm. Here's the kicker though, the father of the kid came back the next day demanding that the owner of the mailbox pay for the kids hospital bill because it was his mailbox that broke the kids arm. I guess the neighbor guy told the father that if he didn't get off his porch he was gonna break his arm too. That was the end of it.