I always recommend that drivers should remain within the legal speed limit. I do admit to having a chequered history on this subject, but at present I have just 3 points on my licence, and those are getting on for 3 years old. I'm looking forwards to driving with a clean licence. So I will not bother to reply to an invitation which arrived in the post this morning, offering me the opportunity to buy a 'laserjammer'. Of course, this device is not sold as such, but as a 'parking aid'. They are even called Laser Park LS and XS Systems.
According to the blurb, police laser guns transmit about 100 pulses of infrared light in one-third of a second at a reflective area of your car, usually the front number plate. These pulses reflect back to the gun, which then calculates how much the distance is changing over time and therefore the speed at which you are travelling. The Laser Park Systems detect these pulses and return their own laser beam at the same wavelength. It seems that this renders your car invisible to the laser gun. Well, I never! You learn something every day.
But of course, these devices are actually parking aids. Their ability to render police radar guns totally ineffective are just an interesting coincidence. The blurb suggests that we think of them as raincoats, which have as their main purpose, keeping you dry. Wearing a raincoat doesn't make you a 'flasher' - but its a very convenient cover if you happen to be one. I really hadn't thought about it like that, but there you go. I'm just a country boy. Anyway, both 'flashing' and 'speeding' are illegal.