I have a story about this and I love to repeat it.
We are members of several FMCA chapters specifically for motorhomes that were produced between 1973 and 1978. There are over 8000 still registered.
A wagonmaster sent us an emergency message that a rally (only about 30 coaches) had to be relocated. At the rally, we got to hear the story:
Wagonmaster had made all the arrangements with a campground he knew about but had never used. While on the backhaul from a prior excursion, he decided to stop there. He went into the office and the attendant (true title unknown) looked at his coach as asked how old it was. He told them the it was painted 4 years ago, had a frame-off six year ago but was the last of its kind made in 1978. Attendant replied that they had a inviolate 10-year rule. To this he replied that they had accepted his an other reservations for a planned rally in the near future. Said person replied that can't happen. He went out to his coach and got the list of registered attendees and canceled all thirty-odd reservations and demanded a check to the chapter for any and all fees thus far submitted. He already had the chapter lawyer on his phone when the check was cut.
We had a wonderful time a campground about 4 miles away that welcomed us and treated us very well. They had been very accommodating when wagonmaster arrived there after departing the prior.
That place does have in interesting rule that says that they will not necessarily allow you long term space unless you have been there for at least one before.
Matt