I remember hearing that same bulletin on the radio that morning. In the past, some have expressed disbelief that even on September 11, there was a "no-evidence-of-terrorism" announcement. I suspect it is more believable after what we have seen of the government and the msm since that time.
Maybe the original intent of the policy, going back several decades, was benign (for example to prevent more casualties due to public panic). But during the reign of BJ Clinton I began to notice its misuse.