Maybe not, but then again, perhaps those cruise lines had those items available already. Carnival can't be expected to go out and purchase specific brands of various food items to satisfy the needs/requirements of every passenger. And on a related matter, is there any reason that you can't simply bring these items onboard yourself? Especially the Carnation Instant Breakfast?! I'm sure that you would not encounter any problem if you so requested such an accommodation. In fact, I have personal experience with this. Just this past March, I wrote to Carnival at access@carnival.com requesting that my wife and I each be allowed to bring aboard 24 ready-to-drink single-serve cartons of Ensure Nutrition Shakes for our upcoming transatlantic cruise the following month due to our chronic digestive health issues. This request was approved in short order. (As someone else noted, Carnival normally allows only 12 non-alcoholic drinks/pp to be brought onboard.) It never even would have crossed my mind to demand that Carnival provide these drinks to us due to our medical condition!