*edit I just got off the Fantasy yesterday. Sorry your child got sick. We are seasoned Disney cruisers (platinum), and I just had to mention that there was a lot of illness on our cruise. (11/26) (probably norovirus, lots of running into throw up in the dining rooms and hallways) I was alerted as soon as I saw the buffet plates gone, soft serve that had a crew member getting it for you and the ultimate was all the drink stations manned by crew during the day and disabled at night with a sign stating you can order drinks from room service. The family hot tub was also closed down and the Goofy and Mickey pool drained numerous times....
I was on that cruise. At dinner on the second night in the Royal Court just as we finished we noticed a CM at the table behind us. He had on a face mask, heavy gloves and was clearing everything off the table and putting it into a heavy duty garbage bag. We all looked at each other and said that we expected to start seeing lock down on the buffet and such shortly. Never saw that family again at dinner. As expected, the next day everything was handed to you. You couldn't even get sugar packets on your own at Cabanas - you had to ask someone to give them to you. One of our travel mates talked to a CM who said that if the CDC says you have to go to some set of procedures when X number of people get sick and higher procedures when Y get sick,
DCL goes to the Y procedures when X number get sick or at least goes to higher procedures when X number get sick than they are required to. No idea if this is true or not. I didn't have any sense that there were a lot of people who were sick (but would I even know?) so perhaps they do go a bit overboard. If so, I'm happy that they do. None of us got sick so who knows if that was luck or DCL taking precautions.
It is a little inconvenient always having to ask someone to put food on your plate as they never pick what you would or put the right amount on but we all agreed it was better than getting sick. Of course, the worst part for us was that we had to ask for the soft serve ice cream so it became very obvious to the CM how many times you went up. It got to the point that they never asked which flavour we wanted, they all knew

. Didn't stop us from overindulging in it.
In 9 cruises and 3 extended overseas trips over the last 40 years I have purchased Travel Insurance just once.
We nearly always purchase travel insurance, not so much to cover the loss of the bookings but more to cover unexpected issues while on vacation. I'm more concerned, especially with a cruise, with the cost of evacuation, overseas or international medical costs, last minute travel arrangements, and incidental costs such as additional unexpected hotel stays for family members. The only times we haven't purchased travel insurance is if we're just going to WDW. We figure we can absorb the cost of losing the hotel and tickets and emergency flights back won't be too expensive. We have out-of-country medical insurance through work so that isn't an issue. But the potential cost of evacuation from a cruise is of more concern to us and the farther away we go, or if we go to places where I wouldn't want the cheapest of medical care options, the more likely we are to purchase travel insurance.
We've never had to collect on insurance but my father has had to use his three times - twice for delays due to snowstorms (he will insist on travelling during the winter) and once last year when he got a lung infection while on holiday in Spain. He spent 9 days in hospital, leaving 3 days later than planned, and then had to have a medical escort with oxygen accompany him on the plane and they had to travel first class because of the need for extra space and faster boarding. He figures it cost about $40,000. Boy was he glad to have insurance. I figure he's not only got his money's worth out of insurance, he's got ours as well.