Why do parks ask for license plate information?

For us it is about 3 things, first for LEOs in event of an emergency issue, verify for our health department another search way in event of a rented or borrowed vehicle, guide LEOs to the registered guest in a vehicle not their own. lastly for us to verify registered guests,identify those not paying for service.
Unregistered visitors add to the cost and liability of the camp, a cost, regretfully that must be passed on.