Taking away alcohol sales will have absolutely zero impact. When I was in Park Services, the trash cans in the parking lot and the bathrooms were full of beer cans and liquor bottles during Halloween Haunt. If people want to drink, they'll find a way. Don't even think about mentioning that they could up patrols in the parking lot, because it's nearly impossible to prevent.
That hasn't been the policy in a long time. Who cares if there is someone drinking beer? It's their business.