Nah, what is being talked about here is infrared light, not any type of radio waves.
Supposed to be that some laser jammers work quite well and will not generate any type of internal error or indication of jamming at the radar device. I would imagine that any LEO's suspecting a vehicle actually did jam his / her tracking device would be a bit cranky and may find other things wrong with the operation of that vehicle or even the vehicle itself. I am not accusing anyone of anything, just pointing out basic human nature- most of us don't like to be one- upped. I am not a LEO, just surmising here. I personally would be careful where and how I mounted the laser RX / TX itself so it was as discreet as possible.
As to the legality, while radio broadcasting is regulated anywhere in the US, as well as most other countries, light emission is not regulated. In the end, LEO laser devices are nothing more than modulated light so emitting light back at them is not fundamentally illegal, excepting higher powered lasers of course but those are already regulated for safety anyway (higher powered lasers can burn retinas). Of course some states specifically target laser emitters so they would be illegal to use in those states. There does not seem to be any move on the federal level to stop their use though; perhaps it is the high price of the units that keeps them from being common enough to be a concern.
Brian
Another not sure if it's true things but I have heard that the jammers really mess with airports and that it is a federal offense. Don't/wouldn't take the chance anywhere near an airport. Personally, I would spend the $$ on a new exhaust 
