I don't want to be part of the debate. Here is an answer to your question. Your carry on is checked at embarkation, looked inside and put through an xray machine. This is what I have been told by the Cruise Director. Before embarking and disembarkation the drug dogs are checking luggage. If they find luggage with drugs in them the dog will urinate on the luggage. This signifies to the drug enforcement agent to pull that piece of luggage aside. I have watched from my balcony at disembarkation and it is amazing because the dog checks every can (container with luggage) for illegal substances. If you disembark and your luggage is sitting aside from everyone elses, you are in big trouble. The authorities will meet you at disembarkation and take you away. If you think you will get around this by carrying your luggage off the ship, think again. The drug dog comes right up to you and sniffs your luggage.