The Jones Act (also known as the Passenger Services Act) does not allow ships of Non-U.S registry to embark and debark guests at two different U.S ports, since travel between U.S. ports is prohibited on foreign flagged ships. Note: Puerto Rico and the U.S Virgin Islands (St. Thomas; St. Croix; St. John) are not in the category of U.S ports under this act.
Guests cannot pre-plan or purposely embark or debark a ship in a U.S port that will violate the Jones Act . Any guest who insists on debarking the ship in a port which violates the Jones Act , will accept responsibility for any resulting penalties (penalty amount is determined by U.S. Customs and Border Protection).
Cabatoge Law is the term used in Europe - Similar to the Jones Act, the Cabotage Law is the transport of passengers between two points in the same country by a vessel registered in another country. This law does not affect guests joining the ship or leaving the ship in different ports in Italy.