One of the first attempts to fool traffic radar was to hang reflective objects on a vehicle, including dangling loose chains, putting foil or steel marbles in hubcaps, and securing strips of foil to the radio antenna. None of these counters did anything to fool traffic radar and, in fact, may have enhanced the vehicle's radar cross-section enabling the radar to detect the vehicle at longer range! Even so drivers that used these techniques were subject to arrest in Rochester, New York, in 1953.
False information circulated on the Internet through massive emails in 2000 and 2001. Basically the scam message falsely claimed by over paying a ticket by a few dollars, mail-in only, and then not cashing a check for the difference when corrected would save you from losing the points. The emails claimed the system would not charge the points until the check was cashed - this was not and is not true and does not work !
Products come and go that claim to interfere with microwave police radar. Be especially skeptical of jammer claims, and in particular any passive jammers. All known passive jammers are useless. Some test indicate not only do these jammers not work, but may enhance the vehicle's radar cross-section. A jammer antenna is a great reflector enabling radars to detect the target at longer range, 10 to 30 percent in some cases. Even so drivers that use passive or active jammers are subject to FCC penalties.
Some hood covers, bras, and license plate covers are suppose to absorb and disperse microwave radar energy thus reducing vehicle detection range. Any reduction is small with only a slight, if any, degradation in radar maximum detection range.
Some license plate covers supposedly disperse laser light denying a laser radar reflections from the license plate. However if the laser is not aimed at the license plate or the beam is wide enough to overlap other parts of the vehicle this method will fail. In fact most reports indicate license plate covers have little if any effect on laser, or microwave, radar performance.