I'll take your mockery as a sign that you don't have much faith in the evidence either. No conspiracy necessary, because the government couldn't act with that much coordination. It is simple human frailty and incompetence behind these alerts, that's all. Try to trace these threats back to a source and they will always disappear like mist. Someone said that he said that an informer said that New York was in trouble....oh yeah, and Washington too...sometime....someplace...what a bunch a crap. In the meantime the public gets jerked around while Tom Ridge covers his ass.
It is our patriotic duty to completely ignore these alerts and the bureaucrat who put them out. Don't change a single thing in your routine because if you do, not only do the terrorists win, but stupid bureaurcrats win too.