I have had a similar event happen with a local nutjob. We were shooting on private property with full permission, after about a half hour of blasting a guy shows up honking his horn and swearing at us. As we got closer to him he sprayed our cars with gravel as he tore off with his truck and then turned around and tried to hit us with his truck. When the authorities asked what he was flipping out about he said that he was afraid that we'd scare his horses... yet the truck he was hotrodding was louder than our gunfire.
I don't know what goes through these people's minds when they confront people they don't know that have guns. What if you were some crazy with a gun and you walked out of the woods to see some hippie writing on your car with a marker? Do these people have no common sense?
I'd do the gamecam thing and go shoot to your hearts content and if it happens again let the judge settle it. I'm sure after paying for your new paintjob they'd think twice before vandalising someones car again.
"A free people ought not only to be armed and disciplined but they should have sufficient arms and ammunition to maintain a status of independence from any who might attempt to abuse them, which would include their own government." --George Washington