"Foreign-flag vessels like Carnival’s vessels may transport passengers between two different U.S. ports without violating the PVSA if the vessel stops at a distant foreign port and the passenger traveled with the vessel to that distant foreign port."
The key part here is that the vessel is not transporting the OP between 2 U.S. ports since they would be embarking in a foreign port. (Bimini)
Like this cruise on Discovery Princess which starts in Seattle and ends in Vancouver.
Sep 21, 2024 – Sep 28, 2024
Seattle, United States • Juneau, United States • Skagway, United States • Ketchikan, United States • Vancouver, Canada