Hello MWH, I have gone through he same issue with Royal caribbean cruise line(RCCL). We carry indian passports. When i called the customer support of RCCL to specifically enquire about this visa - i was told that since the cruise line departs from seattle and returns back to seattle they dont need a canadian visa. So i took their word for it. Also when I did a online checkin ( provided them the passport details - country of issue and other details) there was no flag raised for canadian visa requirement.
Have you considred going to small claims court against the cruise line??? I heard from various lawyers that I might have a case against the cruise line... i just want to get your opinion on that - if you tried at least???