Try to see this as an opportunity, not an obstacle.
If monster truckers and 1/8th buggy backyarders are finding their way to your track - that is potential NEW members for your club.
Run some classes to encourage these guys to come to race meetings. They soon will get hooked and get into the smaller 1/10 scale that suits the track better - or they will lose interest and not be back! Problem gone. Everyone wins!
Just got to get the track a little stronger...