Today, cars, trucks, boats and other vehicles are required to show visible license plates, and airplanes must identify themselves electronically when asked. Recently, new rules require drones to respond automatically to radio signals with their ID. If this drone is accused of breaking a rule, such as invading someone's privacy, authorities can use the registry to reveal which owner is associated with this ID, so they can be sued or accused. Is this a good rule? Should we also similarly require ordinary people to have RFID tags, which respond to a radio signal with an ID, so if that person breaks a rule they can be more easily found and accused?