I too have packed in my bag on all 10 cruises with Carnival. Not once have I been checked. If they find it then I lose it. Its the chance I take. I doubt highly they would ever boot me off the ship. That is extreme. If it breaks or leaks its my issue. I agree that the liquor prices are way too high on board. Bring em down and I will leave my rum at home.
2008-Valor and Glory
2009-Spirit and Splendor
2010-Freedom of the Seas and Mariner of the Seas
2012-Allure of the Seas and Navigator of the Seas