My local park (now Six Flags formerly Cedar Fair) has a whole army of security guards to keep the park safe and eject those who break the rules. They can call the township police as well and sometimes they have an officer or two at the park. Most parks don't tolerate line jumping and there are signs at my local park at the ride queues warning you that you could get ejected from the park without a refund if you line jump. People who have season passes could also have their passes revoked for the season (the security takes your pass) and plus be trespassed from the park for the season or longer, and be made to sign a form informing them of the trespass. That means they can't come back and pay for an admission ticket during the time of the ban or even be on park property outside the admission gates. If they are recognized by security they could be detained and held for the police. An amusement park like the one near me would be a very bad place to commit serious crimes like sexual assault, kidnapping, etc. as the person who did it or attempted to do it would probably be confronted by security and even held for the police to arrest them and take them to jail.