Age Restrictions on Class A's

I've never had a motorhome that wasn't less than 10 years old, and with stays at hundreds of parks, I've never been turned away. I only recall even being asked the age of my RV once, and that was just because the check-in clerk's sister had one just like it and he wondered if they were they same year. That being said, I have stayed in parks for a couple of weeks where they were much fussier about the rig age of long term renters, such as seasonal or year-rounders. I think most parks just use the rule to turn away RV's in poor condition.