Rockefeller and other critics of the industry say that cruise lines that are headquartered in the United States but have their ships registered elsewhere are getting a free ride on the backs of U.S. taxpayers, placing demands on federal agencies such as Immigration, Customs and the Coast Guard, which are charged with oversight when those ships enter and leave U.S. ports.

CNN: July 8, 2012 -- Updated 1911 GMT (0311 HKT)