Campervan area

My mates have bought tickes to camp in campervan area they will have the pleasure or sleeing in our awning, they will be travelling seperately in their own car though, do they need to park their car in the carpark or can they park in the campervan area ?
I know last year there were cars in the campervan area.
In theory they have bought paid for the space ... but i know it may not work like that !

cheers