$10 per person? That is excessive. I've stayed at a KOA that has a resort fee, but it's $2-3 a person. That covers "free" pancake breakfasts, kids activities, hayrides, etc.
For $2-3 I think I get my value (especially with little kids) but we tend to limit staying at places like that. $10 a person is an extra $40 per night for my family. I can't imagine what it would take to make it worthwhile to pay an extra $40 a night on top of regular camping fee's. As a matter of fact, I usually try to stay at campgrounds that are less than $40 for EVERYTHING.