The problem is that Norovirus is very infectious. You only need to be exposed to about 100 particles to catch it, whereas in the case of seasonal flu it's around 10,000 - quite a difference. It's also a survivor. Norovirus can live outside the body much better and longer than many other viruses.
Virus-contaminated food is only one of the vehicles for catching it, but an important one. You can also inhale the virus from the air where someone has vomited, or
get sick from touching an infected surface, or a sick person. You can even catch Norovirus from contaminated ice, as occurred a few decades ago at a football game between University of Pennsylvania (where I went to graduate school) and Cornell, or, at a museum fundraiser for that matter.
Here's what happened (my source is the Centers for Disease Control - CDC report on the incidents). Within 48 hours of the University of Pennsylvania-Cornell football game in Philadelphia in 1987, a large number of band members from both universities, Cornell football players, and spectators, including visiting students and university staff and faculty, all started having symptoms of gastrointestinal illness, especially projectile vomiting and nausea. A smaller percentage had diarrhea, headaches, chills and additional symptoms. These were typical of Norovirus. Almost all had bought soda with ice from the stadium vendor.
Oddly, many of the Pennsylvania football team members became ill several days later. Apparently this team had used ice from a different source at the September 19 game, but had used the contaminated ice at practice a few days later.
Just a couple of days later there was an outbreak of gastroenteritis among 750 people who attended a museum fund-raiser in Wilmington, Delaware, not far away. The ice was traced to the same Pennsylvania ice supplier. It turned out that its wells had been flooded by a creek (obviously contaminated) following a torrential downpour of rain. Probably, in all, about 5,000 people became ill from this Norovirus contaminated ice.
There is no reason why this kind of outbreak can't happen again anytime, anywhere. And there's no way to know that ice is contaminated. Opt for a warm soda?