Not a pleasant term - it has origins from watching other people in day to day situations to listening in to other people conversations ( who doesn't do that ?) to slowing down on the motorway to watch the carnage of a motorvehicle accident on the other carriageway.
10cc's song Rubber Bullets comes to mind ( although that was about the Attica US jail riot in 1971) and there are one or two references to the song - apologies.
