In a city the size of Chicago, there are many more crazy people than there are terrorists.
That's true, by a factor of about 100,000.
I remember for a year or three after 9/11 there were constant "terrorist surveillance" reports on FR and elsewhere, but nothing ever seemed to come of them. These were mainly posted by FReepers over-obsessed with "threats". I stopped reading after a while. Expect the THREAT threads to be resurrected soon.