I agree that it was a step too far taking him to the police. However, I have heard of parents doing it when they discover their child has broken the law. I know my parents would have done it.
Further... Kids do bad things every day and their parents don't haul them to the police station. Heck my son and his friend 'mooned cars' one night over Halloween and I didn't even consider calling the police. Which would be considered "indecent exposure" to those who saw them. That did not mean we didn't address the issue with them when it was discovered. But take them to the police...no.