Steph, my understanding (and anyone PLEASE correct me if I am wrong), is that if you buy booze on the ship in the duty free shop, you can't drink it on the ship. But, if you buy it before the cruise and bring it on in your carryon or buy it at the ports of call we sail into, you can drink it onboard. Also read that you can not take any open bottles of alcohol (wine,beer, hard alcohol) off the ship at the end of the cruise. So on the last night of the cruise I may be really enjoying myself.
If this isn't correct, please inform me of the correct info.
Anne