At the speed they move the luggage from the dock to the ship, I'd bet not all of it is x-rayed. If I were to be so inclined as to smuggle a bottle on board, personally I would opt for putting the booze in a plastic bottle and then in a ziplock bag or two and then into my checked luggage. The carry-on bags are inspected closely and I would think you would run a much higher risk of detection with carry-on luggage. All in all, though, I'm not quite sure why NCL would supposedly be so diligent about trying to nab smuggled booze on embarkation, yet allow four bottles of tequila purchased in port to go right on up to a cabin with a passenger such as happened with us this past week. The booze was right there in all its glory, not hidden at all and no one said a word. Could it be that some of these agents are simply asleep at the wheel?
Now as far as soft drinks go, with NCL all you can seem to get on board is Coke or Diet Coke. My husband was offered a very rare Diet Sprite while dining in Cagney's but I believe the waiter told him that is only available at the Star Bar. The servers with the carts might have had Sprite as well but I did not see Sprite offered at any of the bars. Why, I don't know because Sprite is a Coca-Cola product. Not everyone likes Coke or Coke products. What if you prefer Pepsi or Dr. Pepper? What if you prefer decaffeinated cola? It just seems to me that they ought to allow you to carry on board that which they do not offer with the soft drinks.