You ignored my response. If noro was airborne beyond clearly isolated incidents that this lawyers website latched onto (read carefully where it came from as there's no links to the study in either that article nor the one linked from) then people would be sick endlessly on cruise ships from that, the flu, common colds, and every other virus thats airborne.
Reality is, again...it does not happen. Never been sick on any of our cruises, nor have any of our (extensive) friends list who also cruise.
Your views of sanitation on cruise ships is quite off base. They are cleaning and sanitizing literally constantly and the air filtration and exchange systems are also working to avoid these issues. Your apparently preconceived notion that they just don't clean anything unless there's an outbreak couldn't be further from reality.
You do realize that nearly 40 million people a year take a cruise, right?