Got back Sunday from our cruise. We used the Rum Runner Cruise Flask, and was able to get plenty of coconut rum onto the ship. Costs $8.00 on Ebay, and held 2 bottles (1 in each flask). Comes with a funnel, and are heavy duty clear plastic baggie type container with a leak-proof screw on cap. Fill it up, and put it in your luggage tucked inside clothing. X-Rays can't detect them.
Our next Cruise came with the Ultimate Beverage Package, so we won't need them then, but they do work as advertised.