From the City of Brotherly Love and Martial Law I post on this Yom Kippur...

I do not believe that in the history of the United States has a major metropolitan area been so remarkably cordoned off it has been here in Philadelphia. They are not only placing high fencing in a lengthy perimeter around the Center City region, but major arterial highways are going to be closed for long stretches of time. Unless you live here you cannot imagine the extent of the disruption to literally millions of residents and thousands of businesses. I am slack-jawed at the measures which they have taken and are going to take. The preparations for security for this event have been unceasing since the announcement: thousands of personnel, cables, radiation detectors, cameras, and electronic gear which looks like George Lucas designed them for the new Star Wars film. The logistics for each of us who have to be in Center City for the next five days is staggering: the rules for walking, driving, parking, opening ones business, going to restaurants, etc. are complex beyond comprehension and changing by the moment.

This I believe is unprecedented. I wonder at the reasoning and have several hypotheses, none of which are positive.