Hmm, I though about the overselling possibility but then it seemed a little less likely since we have always seen the website update the # of cabanas left in real time. Also, we received an "early invite" email and booked right away. We have a Crown Loft Suite and are Diamond members but I guess it is possible that there are that many Star Class guests guests that booked ahead of us. In my experience they would not bump a Sky Class (or below guest) for a Star Class guest to purchase after the fact. We have usually sailed Star class and if an excursion is full we have never been offered to "bump" someone. Not that we ever would do something like that anyway, but that seems like a crappy thing to do to someone that booked before you.