Many do to one extent or another. Embassy does it and Marriott doe, Westgate has been bullying it's owners trying to resell. Get your hands on the latest edition of Timesharing today, the lead article on Westgate. Actually many systems have this wording in their paperwork, some are far more active than others in acting on it. Maybe TUG would be the place to post a question about HOW has a ROFR. You might even search on TUG, I wouldn't be surprised it it's been asked before. I'm not sure about the others you post, I bet Lisa P. will know at least some of them also.