It seems to be the 'luck of the draw' with bringing liquor on board and varies by ship/line.
I think you will find that the large bottles of alcohol, brought in with you as you embark, will probably be confiscated. However, if it is packed in your checked luggage, it should be no problem. I usually purchase miniatures and wrap them in baggies (just for safe keeping) and intersperse them in my checked bags and have not had any problems.
I had never had trouble with taking liquor onboard that was packed in checked luggage until this past January. I was traveling on Celebrity and they were scanning all bags as they were loaded onboard. Any bag that had anything that appeared to be liquor was confiscated and you had to report to security to open the bag and they removed the alcohol and kept it until the end of the cruise. Beware!
the last couple of times we cruised we emptied out 1.5 liter water bottles and filled them with vodka and whiskey and carried it right through security...no problem, all they saw was plastic water bottles and off we went. also did the same thing at a port of call and bought a bottle of water, drank that and filled it with sky vodka, no problems! great trick. one time we also packed mini's in our carry on(like the one's the airlines serve) they saw those and took them out and tagged them in a special plastic bag and we got it back the last night.
I just got back from the Voyager of the Seas and had no issue bringing my Vodka on board. BTW you could buy liquor in the gift shops and pay an additional $10 and they would let you drink it in your cabin.