113 passengers reported being ill on this cruise, which means 1940 passengers either didn't get sick or didn't report it. Of the 838 crew members, 12 reported illness. Not what I would call 'class action' territory, even for the most predatory lawyer. I suppose Princess is liable because some passenger lied on their medical affidavit and boarded knowing they had recently had the stomach virus?
By the way, the Sea Princess was inspected by the CDC on 5/24/2011 and received a sanitation score of 99. Almost perfect score.