I've got no problem with not getting a reservation fee back when it is my own situation that I can't get to the campground. When I have had to cancel, I do ask if I can get a credit for future use. We are doing that this fall... last year we had to cancel a camping trip with a no return policy reservation, but were able to get a credit and are using that this fall.
Abusing the reservation system is Rampant at Disney World's Fort Wilderness. It is openly discussed on forums. It has been a few years since we've been there, so maybe they've added more rules to try to combat this.