Laser jamming, since it does not involve the transmission of a radio jamming signal, is perfectly legal as far as the feds are concern but is illegal in some states. Still, most laser jamming really only buys you most time as the jammers have a more difficult time tricking the lidar unit at closer ranges. But it's better than relying on a radar/laser detector alone, which must be hit by the laser (too late, usually) or get a fairly concentrated reflection as the lidar beam hits something else close by.