Norwalk virus makes it sound so ominous. It would be much less interesting if called "stomach flu", Which it really is, and is certainly less notable at my daughter's grade school that was closed for a few days when there was an outbreak! Disney's outbreak was no more statistically significant than most elementary schools, but far more newsworthy!
I am a nurse and 'tis true that this can come from cross-contamination (Nosocomial infection), like almost any virus. Norwalk is a hand-to-mouth disease and is very highly contagious. Any competent nurse would be using appropriate universal precautions. Of course not all health care workers (nurses and other depts included) do this. And unfortunately, with a susceptible population, there will be outbreaks no matter how conscientious the caregivers are. As the CDC says, Norwalk proliferates anywhere where people are confined together for a period of time. School, resorts, cruise ships and hospitals/nursing homes are on that list! On the advice of an epidemiologist at work, I have started to carry antibacterial hand sanitizer with me on top of observing proper handwashing techiniques, and gloving for nearly everything. Many studies have shown that both health care workers and lay people do not observe effective handwashing techniques, which includes a 3 minutes scrub, under the fingernails, and up to the elbows. So the sanitizer covers what might be missed.
The elderly are immunocompromised as a function of age and other illnesses. Norwalk is a very opportunistic infection, that will infect everyone without prejudice, but is far more dangerous in the elderly and ill.
My family is cruising in 2 weeks. I am no more worried than I am to send my children to school. I will take precautions, and encourage my kids to do so as well. Disney keeps popping up in the news simply because it is a name people recognize.