The Los Angeles Sheriff's Department is experimenting with a squad-car-mounted image processing system that detects and reads license plates, then matches them against a list of stolen cars' plate numbers. During one night of testing, four squad cars automatically looked up more than 12,000 plates, which resulted in seven recovered cars and three arrests.
You've got to feel for criminals who suddenly find themselves up against cops with vastly improved processing power--in effect, a brain that can memorize and instantly retrieve thousands of license plate numbers. It's only a matter of time before these systems are mounted at intersections (integrated, perhaps, with photographic speed traps)--tailpipe sniffers that detect unacceptable emissions will arrive shortly after that. Something similar is in the works to help police officers recognize faces, and I have no doubt that pheromone-based systems that use amplifying prosthetic noses to detect guilt are being developed by cheerful researchers.
In short, the civil authorities seem poised to have unprecedented powers of investigation at their disposal--ironically without, technically, invading your privacy at all: license plates, tailpipes, and faces are all clearly in the public domain. The world is becoming a very different place...between this and rap "music," I'm tempted to join a soybean commune somewhere out in Montana. I'll see if they have room for you, too.