When we have the offers from the 'other' infamous CT casino and the ones from Vegas, they have an exclusive TA involved & doing all the details, including any air & ground transportation, and insurance is (sometimes) mandatory but reasonable. You can add a person to the cabin but they can be close to the rack rates listed & not necessary the lowest then available rate - and you are likely to NOT get credit for the cruise as it's not cosidered a regular fare (some do, check the fine prints on page xxx :D and the cruiseline's website, etc.)
These land-based casino offers done in partnership with the cruiselines are generally NOT transferrrable as it would otherwise be 'bartered' (translation = sold/exchanged) to others, discounted or otherwsie.