Site-specific Ressies or whatever's available? Preference?

I worked in a CG that would not let you reserve a specific site ! The main reason for that policy was , suppose you wanted site # 12 , the camper in there left on Wednesday and you wanted it on Saturday . We could not let it set empty for three days just because that you wanted it . We might have a camper sitting there with cash in hand wanting that site . Popular sites sell without reservations . We have many times suggested that you might pay the down time to hold your spot , many did just that .