Thank you for sharing your experience. I was worried about the buffet on Lido deck when we board. My daughter's doctor has her trying her allergic foods one at a time so she will know what kind of a reaction to expect if she accidentally eats something she shouldn't.
I called Carnival soon after the food allergy diagnosis and they faxed me the special needs paperwork. My plan from the beginning was to fill it out and return it (but have waited to see if she had more allergies since the testing wasn't complete) since I tend to be overly cautious about things like this.
I think some people may wait until they get on board the ship to discuss it with the dining room because of this posted on the page for guests with special requirements:
Dietary Needs
Carnival Cruise Lines can provide meals to our guests with the following special dietary needs: vegetarian, low-cholesterol, low-fat, low-carbohydrates, low-sugar, gluten-free, and Kosher. If you have food allergies, please advise your dining staff once onboard, or contact a Guest Access Services Representative to discuss your requirements.