Just so you are aware - infrared LIDAR does not LOCK ON anything. Rapidly pulsed beams of infrared light are reflected off of the moving target back to the instrument. The difference in the amount of time the pulses take to reflect back to the instrument is calculated to determine SPEED and DISTANCE. It only takes about 1/3rd of a second to get a reading. The aiming reticle allows the operator to see which target he is aiming at. There are many highly reflective surfaces on a motor vehicle, the license plate usually being the most desirable target due to its reflectivity. A car's headlights are also very reflective, along with chrome trim and bumpers. Because a plate is missing does not mean that a reading cannot be obtained.