I don't think people are getting sick from Coral Reef. I do, however, believe that unsanitary dining guest habits at buffets could be a culprit. Regardless, we still plan to eat at both when we go in a few weeks.
I'm thinking a friend of the coworker just started a rumor to keep their favorite restaurant from booking up Ya know...didn't you hear about the cochroaches at Le Cellier?
I read the Sentinel almost daily and haven't seen a thing. We also ate there on our most recent trip and not only did we not get sick, but we had the best meal we have ever had at WDW!