Radar detectors, while excellent at what they do, are not perfect. One of the biggest differences between the lower end and the best radar detectors is the number of false alerts given by the device. For example, a common police radar gun shares the same K band frequency as a lot of other common devices such as automatic door openers and the blind spot detectors of many vehicles. Thus, false alerts may be a story of boy cry wolf for real threats and fake threats. To learn more about the differences between the radar bands that radar detectors can detect, see our Differences Between X band, K Band and Ka Band article.
Luckily, premium radar detectors such as the ones from Escort and Radenso are set up right to filter out false alerts, so that only real law enforcement and their LIDAR radar guns are detected.