Did a little reseaech on RCCL's web site. Here is a copy of their policy.
Can I bring my own liquor onboard at embarkation?
Guests who purchase liquor onboard a Royal Caribbean International
vessel from one of our gifts shops, for in-cabin consumption, will be
sold the liquor at an in-cabin consumption rate (non-duty free rate
which is comparable to retail rates), which in turn can be taken
immediately to their cabin.
If a guest decides that they would like to purchase duty free liquor
from any of our gift shops, then they will pay the duty free price and
their respective liquor purchase will be delivered to their stateroom on
the last night of their voyage.
In addition, any liquor purchases that are made by a guest in a land
based location, will be stored onboard when they enter the vessel,
and will be delivered to their stateroom on the last night of their
For those guests who bring wine and champagne to celebrate a
special occasion onboard, these products will be tagged and stored by
our personnel, and delivered to the guest stateroom or their dining
venue, as per their request. If these special wines or champagnes are
consumed in our dining room or specialty restaurants, or in the
Windjammer Cafe for casual dining, a corkage fee of $8 per bottle