It not only depends on the cruise line, it also depends on whether the scanner is in a good mood or a bad one.
Disney Cruise Lines, for example, states on their web site, "Alcohol is permitted on board. However, any fragile items (including alcoholic beverages) must be hand-carried on board in the carry-on of an adult Guest – age 21 or older (dimensions can't exceed 22" wide, 14" high and 9" deep).
Alcohol brought on board may not be consumed in any lounge or public area.
Guests who arrive in the dining room, including Palo and Remy, with a bottle of champagne or wine will be charged a corking fee of $20.00 per bottle.
Please be advised: Disney Cruise Line reserves the right to remove fragile items (including beverages) from checked luggage. In such cases, items will be stored and returned at the end of the voyage. Beverage containers are considered fragile and have previously caused damage in checked luggage. All fragile items must be transported inside carry-on luggage."
Most of the other lines will confiscate bottles that show up when the luggage is scanned.
We just got back from the Caribbean Princess. We used the Rum-Runner Flasks and they worked fine!