[Orbiter]

I'd disagree to the extent that mass panic might prove more irksome for our Homeland defenders than a couple of hundred thousand collateral damagees. A better barometer of things known but better left unsaid might be keeping an eye on who stays in town that weekend versus who's hightailing it out for "scheduled" meetings.

[Toespi]

I have thought of the same thing, if there were a planned mass attack the feds would be scrambling get a handle on it and try to get it stopped. Early warning to the public would be counter-productive.