In the UK, traffic cops used to have "Black Rat" stickers [0] on their personal vehicles (for various reasons they are nicknamed Black Rats- this started out as

In the UK, traffic cops used to have "Black Rat" stickers [0] on their personal vehicles (for various reasons they are nicknamed Black Rats- this started out as a derogatory nickname from other police, but they adopted it as a point of pride). Once it became clear that the stickers were being sold to the public, they stopped working as a way to avoid being pulled over. [0]http://bluelightgifts.org.uk/stickers/ http://bluelightgifts.org.uk/stickers/