The problem I see is that jamming GPS / wifi / mobile frequencies once you see a suspicious drone is too late. When the drone is already in view, it can find it

The problem I see is that jamming GPS / wifi / mobile frequencies once you see a suspicious drone is too late. When the drone is already in view, it can find its target by inertial or camera navigation alone. But jamming 1km around every possible target, every day as a precaution is going to be too disruptive. It may actually increase risk to life - by jamming 911 calls for any ordinary accident.