I've seen this topic go back and forth several times. From what I've seen, if your RV is clean, not dented, has all the exterior lighting working, has good tires, and the tow vehicle isn't a wreck, almost all of the parks will welcome you. Only the "resort destination" parks adhere closely to this rule. When the office manager at the park answers the phone, and is asked about the "10 year rule", they have to say that they enforce it. It may be an insurance agent calling to verify, or the owner calling to see how the question gets answered. There are two Airstreams in my park, over 30 years old. They are the best looking RVs in the place.
Mine is 15 years old. When I wash/wax it, I can stay anywhere. Central Texas has one of the lowest unemployment rates in the country. Places like Austin are very desirable places to live. An RV park will have it's choice for residents. Saying they enforce the 10 year rule weeds out a lot of RVers. Go East, toward Bastrop. Parks there are more relaxed.
Bama Duke