Western democracies have deployed video monitoring systems in places like airports and busy city districts for years. The largest-scale deployment to this point is the U.K.'s 4 million video cameras; you see them in practically every public place. The systems are generally sold to the public as a means to reducing crime in public places, but so far, they're much more useful for investigating crimes after the fact than for preventing them. In other words, results of these deployments so far are mixed, tending toward poor. But the deployments go on.

The People's Republic of China (PRC) is now running a very large-scale pilot for video monitoring in Shenzhen, China (20,000 cameras), coupled with smart residency cards containing a lot of personal information for the majority of the population of that city (a total of 12.4 million people). Details can be found here (link requires a password).

Given the relative lack of restraint on what the PRC can do with its citizens, we may find the Chinese pioneering uses for these systems. Certainly, the PRC can experiment more aggressively than most Western governmental agencies. The potential for combination of large-scale video monitoring with detailed personal information, obviously present in the PRC's experiment, is particularly interesting. No Western government has experimented with this approach on this scale; so far as I know, the largest facial recognition system database deployed publicly was Tampa's, which included a database of over 10,000 wanted felons, sexual predators and runaway minors. That's a small database indeed compared to the population of Shenzhen, and the Tampa database was aimed only at people already known to be of legitimate interest(in Western terms) to the police.

My guess is that Western democracies, which have employed plenty of video monitoring systems in the past few years, will be watching the Chinese experiment carefully for clues on how to make these systems more effective. The question is whether Western democracies will be willing to do what the Chinese will have to do to make the systems effective.