Wary Citizen
Someone who will ring the police at the first sign of trouble. Usually a neighbour, will look out the window and watch for troublemakers. The wary citizen will see someone drop a receipt and call 999 wasting the emergency services time and the wary citizen calms down as soon as they arrive. The emergency services will leave and the wary citizen will feel proud that they have managed to look after their community. They are mostly pensioners living in the south of England with nothing else to do with their time.
Random Guy: That guy just kicked a stone.
Wary Citizen: That's it, I'm calling the police!
Wary Citizen: That's it, I'm calling the police!