Hard to say. At this point if they claim the sky is falling and nothing much happens it could mean their reputations go down the tubes along with the risk.
I suspect everyone involved is doing their best to evaluate it correctly. Too much is on the line to do otherwise.
For all of you who are laughing at SARS now, all I can say is, I hope you are right. I am usually one of the first to ridicule the media coverage of imaginary threats as sensationalist, but this time I just don't know.