Read Three Felonies a Day (http://www.threefeloniesaday.com/Youtoo/tabid/86/Default.aspx), then apply this type of technology.
The problem is not so much with facial recognition, it is that basically everything is, or can be construed as criminal. Up to now it has not been practical to catch everyone for everything, but the time is approaching. It used to be that DNA testing was only used for the most egregious murders and rapes, but now teenagers are given criminal records of their saliva is found on a beer can. Fooling with a flag on a New York bridge is no longer a source of amusement, it is a now considered a national catastrophe which justifies the cameras that follow us everywhere.
In addition, the consequences and punishments are so badly out of line with the "crime", that we have become a self-censoring, robotic nation.