I heard a funny story about a speed camera that flashed at every one passing. Somehow this was done to use up the film, maybe because of the due date. The Norwegian cameras take the picture at the front of the car, because they need to identify the driver.
Anyway, this one guy passed and noticed the flash. Then he turned and passed again to verify that he had the correct speed... then it flashed again. Annoyed by this, he turned and passed again driving 10 km/h below limit, and it flashed even now! He then gave up.
Some days later he received 3 tickets for not wearing his seat belt
This is allegedly a true story.