Are there any other categories open (oceanview, balcony, etc)? If so, they may not even have inside staterooms available but are trying to sell those last few staterooms of the other categories in any way possible.

I.e. Say there is a balcony cabin and a mini suite available. This close to sailing list guarantees in all lower categories plus those real rooms. This way you can grab someone that only wants a specific room OR someone who is just looking for a deal. And as soon as 2 rooms are booked - in any way - all of a sudden nothing is left available. If the specific rooms are booked, good they got what they wanted. If they booked the guarantees, the cruiseline either upgrades them to the two rooms that are available OR upgrades somebody already booked in an inside and then gives those insides to the new bookers.