Some police agent use waze account to create fake alerts randomly or to say "control not here anymore" when they are doing control. These wazers can be identified by the system simply.
If a police agent uses waze, his location is tracked by the server. If a police agent is using waze while doing a control, his position will be standstill until a normal wazer spot him. So there will be an alert at the place the police control is located. The waze server can record these habits and conclude the user is a cop and limit his actions.