I would suggest that the situation with SARS was a very specific and very rare occurrence. It was judged to be a national medical emergency. And the people in question were not yet sick, but it was feared that they might be sick as a result of contact with SARS, and so in an effort to get people out of the workplace and let them leave the workplace as quickly as possible, there was a deferral of the two-week waiting period in that case.
In my memory, it was the only time in which this has happened, and it surrounded a medical emergency of quite serious proportions, so I would put that on the table.