Excellent idea. As we all know, pattern recognition software is always perfectly written and thus never ever produces false positives or false negatives. It's also clairvoyant and can detect Bad People who do Bad Stuff even if they've never come to the attention of the authorities. There's no possibility of any racial biases being programmed in by humans - after all, machines can't be racist. Every single one of the most dangerous criminals are also stupid enough to hang around the Panopticon a city like London with its cameras all over the place.