No, sadly it wasn't. IANAL and neither was the customer service person at the cruise line who cited the Jones Act to me, but to my understanding, it applies because passengers technically count as cargo. Therefore passengers embarking on a ship leaving the US cannot disembark and not return on the same vessel.
I was trying to find something and it seems to be the Passenger Vessel Services Act which is now part of the Jones Act. I think the travel agent understands the rules incorrectly though.
