I'm amazed at the amount of vandalism that you seem to get. I put new seats in my theatre in 1989, and they are still almost like new. Over the past twelve years, I've had to replace about a dozen seat covers, and three or four backs. My biggest problem is that we have a wood floor and some times the screws pull out of the floor, and then the hole left behind is too big to put another screw in. Our solution to that is to send someone down into the crawl space below the auditorium while I drill a hole and drop a bolt down. The person below puts on a washer and nut and tightens it up, and... no more problem!
I will admit that when I aquired the theatre back in 1970, there was hardly a seat that wasn't slashed in one way or another. we recovered all those seats and made them last another 19 years until I put in the new ones in 89. Those first 19 years we lost about 20 seats a year to vandals, but after putting in the new ones, it stopped. Were they trying to tell me something all those years?
On the other hand, we seldom see a teenager any where near this place anymore. It's more like an old folks home. Mirrors the owner I guess.