Agreed. And I wouldn't take a salesman's or even a club owner's word for it. I would get in touch with other club personnel and more importantly someone higher up than the personnel of any particular club.
I've known a few people who has gotten totally screwed this way. Paid a huge fee for a lifetime membership that wasn't honored at other clubs, and some that have just paid for a year or two and not had that membership honored at other clubs, despite it being written in the contract that it would be. I have a feeling that this might be a fairly common scam, since I've heard it so often. By the way, the latter version of this scam happened to me personally, too.