A security researcher named Kevin Finisterre managed to tap into the live video feed of a police cruiser camera. He was able to do this because the systems that the police department used were insecure and used protocols such as FTP and telnet. Due to some configuration error no authentication was required and Mr. Finisterre was able to stream live video from the camera of a police cruiser.
The documentation of his audit can be found at http://www.digitalmunition.com/OwningCopCar.pdf
I came across this story a while ago but it is still pretty interesting. Imagine the possibilities.