You could be under active, persistent public surveillance with no way of knowing it is happening, and this would be totally legal in many places. Why is his be

You could be under active, persistent public surveillance with no way of knowing it is happening, and this would be totally legal in many places. Why is his behavior illegal? What law is he breaking? Public nuisance, maybe? Your reaction depicts the typical attitude to surveillance. What this guy is trying to point out is that we are already under surveillance and we have no control over it and no idea who is doing it or how thoroughly they are doing it.