I think one of the reasons they're not talking about it is for out-of-town relatives who can't get in touch with their loved ones.
I've noticed each time they talk about the dead, they seem to preface it with "don't be alarmed if you can't get through, there's a 99 percent chance your relatives are fine."
If they created a nation wide panic they might have relatives pouring into the area in droves trying to locate their loved ones, and they can't handle that right now.
That's a good point, and may well be the rationale.
excellent post