I think this may have been verified already but the following is an email I received a couple days ago from my TA
New RCCL announcement just came out regarding the All you can drink alcohol packages.
It said they will be rolling it out fleetwide. I'm not sure of the dates for each ship though. Supposedly this is online. I looked, but didn't see it...I only did a quick, brief search though.
From what I read, there are 2 packages, and if you want them, they can not be pre purchased before you sail. You must purchase them only on the 1st day onboard, and if 1 person in the cabin purchases it, the other adults must purchase it as well (to avoid sharing).