We brought 2 bottles of wine in check in and the Room Steward iced it down for us. As far as hard liquor people who brought it in their checked luggage got it in no problem. However I would pack it in bubble wrap of course and pray it didn't break or instead of saving money you will use the laundry facilities. Also we left from gulfport and never went through customs on debarking.
My allowed bottle of wine was noticed under xray in Baltimore before boarding. Custums went through my carry on at a table three feet from the line, no privacy. He checked the seal and the label, and sent me on my way. No one noticed the rum bottle packed in our checked luggage.
I have NEVER had a problem bring on hard liquor or wine either at embarkation or at the ports of call. You just have to plan a little, and not flash it openly. Carnival, like all lines are fairly lax in enforcement... IMHO .
I went aboard Fantasy with 3 bottles of wine in my carry on, of which I never had a problem. Each of the three nights we brought one bottle to our table and were happy to pay the corkage for our party of 4. I am in the business and loved bringing some of my special bottles for our special trip. In other occasions, we have brought our beloved gin and tonic in our checked baggage. Those plastic flasks are great! "Oh cabin steward....plenty of ice please!!"