I'd go along with Santikos on this one. Our drive-in suffered the same problem. $5 carload pricing in two of our fields gave the kids a dark, cheap, relatively unsupervised place to congregate. Along with that came problems with alcohol, attitude, vandalism, and complaints from the customers who had come to watch the show.
The fix was to go strictly per-capita. We have two price levels... general and child(senior), and our child's price is not rediculously below our general rate. Over a season or two, our customer issues nearly vanished. There was a little whining, gnashing and grumbling, but the end result was a growing, happier customer base that no longer had to deal with the kids' party attitude. There were other positives about dropping carloads... booking being among them, but the change in our crowd was very noticeable. It's sure a lot more fun for us now.
The lesson for us? Your customer will generally respect your product and facility in ratio to what he invested in being there.
Oh... just remembered. We once had a small, single screen indoor theatre in a logging town. Looking for that extra buck, we had a dollar night on Wednesdays. The place was usually filled to capacity, but we also had the noise, vandalism and security issues. Being in an area with competitive high schools added to the problems. A lot of the dollar crowd don't spend much in concessions, either. We dropped the dollar night and things calmed down a lot. Then, the landlord sold the building to the power company, who turned the place into a garage... but that wouldn't help much in your situation!
[This message has been edited by rodeojack (edited March 08, 2008).]