www.abc.net.au/iview/#/program/30857 This doco featured a week ago on the ABC Four Corners and showed what's happening on the ground in the US.
I've been to the US in 2009, 2011 and 2012. Personally, I didnt see anything to the casual observer that was different to when I was there in 1997 except body scanners at the airports.
I saw it a couple of years ago. Was driving out of downtown LA and got a bit lost. Only a few blocks from the CBD and ended up in a bit of a ghetto neighbourhood, mostly african american and project apartments... stereotypical cyclone wire surrounded basketball court with all the neighbourhood kids playing a game. Suddenly everything stopped and everyone bolted across the road in front of us.... scared the shite out of my mrs who screamed and thought they were after us... turns out a food van (like meals on wheels) had pulled up and caused a stampede.