If the U.S. State Department and Department of Homeland Security are issuing the press releases, updating their websites, informing all other world governments and advising this, I think I would believe them long before I would believe a travel agent.. Granted it has to be rubber stamped by Congress. The chances of this not happening are about 1 in 1000.
The cruise lines have no authority as to which documents are required to enter or exit the United States or any other country. If the United States State Department or Homeland Security requires a passport that is what you must have.
With the fact that the State Department and Homeland Security have made the proposals and that there is about a 1 in 1000 chance that Congress will not pass it, her statement was at the least, naive.