Not ethical? Whatever.
RVs are notorious for their contracts. That's why NSW standardised the contracts (7pages, I believe). People who buy into this places do so on the basis that they'll never move again. Then when they do have to move, it's somebody else's fault they didn't analyse what they got themselves into. Quite often their kids will advise against moving in, because they can see where their inheritance is going. Caveat emptor.