5 How to beware of bicycle thieves? Don't talk about the 24-hour surveillance video. The camera often generates a large amount of image data. Even when theft is recorded, it is often ignored during playback. In the United Kingdom where surveillance video is very popular, more than 500,000 bicycles are stolen every year, of which only Less than 5% can return to the original owner. This passage mainly states:. ['Bicycle theft detection rate is very low.', 'Be more careful when playing back surveillance video.', 'Bicycle theft is a very common crime.', 'The use of surveillance video to prevent bicycle theft is not effective.']