I was told by staff, that they do try to up-grade to higher categories, if the ship is not as full. I was told they do this at the last minute in order to get more people on board at cheap prices. They make it so they can do last minute cheap getaway options. NOw if there is some cleaning or maint. that needs to be done on a room, of course they will keep that one empty. After all this is how they get you "hooked" with the other rooms. I know it worked in our case. We now pay for the higher cat. becuase we like the room. Have fun.