Realistically, if you wanted to do such a thing, you could have used a Kinect for a long time. Even face detection would work in your example, and we've had rob

Realistically, if you wanted to do such a thing, you could have used a Kinect for a long time. Even face detection would work in your example, and we've had robust and cheap detection for a long time. So I assume that this is a movie-plot threat. However, for a dramatic interpretation of your query, I suggest "Daemon" and "Freedom TM" by Daniel Suarez. The book shows groups using these technologies to great effect.