My take on this revelation (especially the release of it) is that there is some threat that has been picked up in all that 'chatter' they mention. How can you ramp up security w/o letting the ticket holders know that there might be a problem and patience is needed? You don't tell them Sunday afternoon in parking lot while they tailgate. Just my thoughts...
I do know that for days leading up to the Superbowl there were several aircraft combing the area at low altitudes, both over Detroit and Windsor. I read somewhere that we have radiation detection capabilities in aircraft. Who knows, but it wouldn't surprise me if that was what they were doing.