Thank you for sharing your experience.
Coincidentally, I was talking about this with friends last night and used the example of someone who lived in, say, Ft. Lauderdale, who could get on a cruise without flying there: why wouldn't the AmEx Platinum insurance benefit apply where that person starts and ends the "round trip" by "common carrier [which includes a ship]" on a cruise? So I was interested to hear about your experience. I just don't see where RT airfare is required. The other thing is, I had heard that where airfare is included in the total cruise price(for example, Regent), there might be a loophole that would result in a denial of coverage. I don't see how both things could be true. There is also an issue with "A. . . . you must charge the full amount of a Covered Trip to your Eligible Card or in combination with your Eligible Card and accumulated points on your Eligible Card or redeemable certificates, vouchers, coupons, or discounts awarded from a frequent flyer program or similar program." Does this mean "full amount" to the traveler? So for example, you get a RT ticket through points plus a small amount, is that the "full amount"? (I know the Points Guy says yes -- and I would agree that's what it sounds like - - yet others out there have questioned his conclusion.)
To show how ridiculous this is - - if all this is true, since the significant point seems to be the purchase of a RT, this means to get coverage, the traveler could buy a cheap ticket from someplace to the point of departure. For example, drive to a city 3-4 hours from where you live, stay in the airport hotel, fly to the embarkation point, drive home after the cruise. If this costs you a few hundred dollars, it's still a lot less than $2000 (typical cruise insurance policy). In fact, does it even matter if you actually fly? This is meant to show how ridiculous this is.