I was able to book our first cabana (on Serenity Bay) for my wife and I when we were still silver. Non were available when I first booked excursions, but I kept checking and eventually was able to reserve one. The only time we cruised concierge (in the Walt Suite on the Wonder for my wife's 60th birthday) we booked 2 cabanas on the family beach for our group of 15. Unfortunately we were unable to dock at Castaway Cay due to high seas. The last cruise as Platinum, I was unable to book a cabanaUnless you book concierge, your odds are always low - regardless of the cruise date.