Shock Belt Yikes – something I hadn’t heard of, from the Wikipedia:

A stun belt is a belt that is fastened around the subject’s waist, leg, or arm that carries a battery and control pack, and contains features to stop the subject from unfastening or removing it. A remote-control signal is sent to tell the control pack to give the subject an electric shock. Some models are activated by the subject’s movement.

The United States uses these devices to control prisoners.

There’s a lot to debate, but this strikes me as a technology that’s going to immediately be misused if it ever hits the general public.