These clubs have a membership fee, which is partially refunded upon termination of your membership.  Commonly you will receive a percentage of the membership returned upon termination.  Should the value of the membership grow over the duration of your ownership at the time of termination it may be that the destination club would offer a refund of the “future value” of the membership deposit, as opposed to a straight percentage (80% to 100%) of the membership deposit amount that the member paid initially?