We need a law or court ruling pretty quickly in the US that sets the standard that a group of people have no more or less rights than an individual. This will required LEA's to provide probable cause prior to any actions against groups of people (such as this).
Ain't gonna happen - are you kidding? If there is a ruling like that, it'll be done in some way that restricts citizen rights rather than expanding them, or expands police powers rather than restricting them. It's already legal for cops to hang around street corners watching for suspicious activities or suspicious people, and all video recognition technology does is increase their effectiveness and speed at doing things they already are allowed to do.
Unfortunately, I'm being increasingly forced to take the David Brin position of "Cameras are cheap, get used to it, just make sure we have more cameras pointing at the cops than they have pointing at us, and make sure the cameras the government has are citizen-accessible as well."
An alternative is a new religion, The First Cypherpunk Church, whose members are admonished to wear identiy hiding (oops, I mean modesty enhancing) garb, like arab women. Then we can all go around anonymously in public. Of course, you'll stick out like a sore thumb and may look like a fool unless enough parishoners join, but.... --Steve