If they were prescribing an OTC anti-diarrheal...maybe a medical FReeper could weigh in because it’s my understanding that those can prolong the infection, and that dehydration is the biggest concern with noro.
In which case, at least in this instance, the carrier might have needlessly exposed itself to further liability.
You are correct, of course, re dehydration. It was dehydration that sent me to the ER in Hawaii after eating some canned abalone from New Zealand. The doctor gave me some OTC Imodium and when I suggested a more aggessive approach he assured me that would handle any variation of the problem I had.