Back in my pre-retirement life, one of my duties was as a training officer which included certifying other officers on LIDAR and RADAR. Please allow me to address a few of the issues raised in this and other similar threads.
As for the OP of this thread, to demonstrate the sensitivity and pinpoint ability of the LIDAR unit to the new operators, I would have them clock people on bicycles or even joggers at a range of two to three city blocks, which the LIDAR units will easily do. Based on that information alone, I'll let you be the judge of how well "special paint" or any of the supposed LIDAR countermeasures would work.
In my career, I heard all of the RADAR and LIDAR countermeasure urban myths and legends (btw, the TV show Myth Busters did a traffic RADAR countermeasures myth episode). Think about it - if there was a cheap, easy, effective way to jam or reduce the range of RADAR or laser, Uncle Sam (and our enemies) would be using it instead of the billions of dollars spent on "stealth" technology, which even at that level of expense and technology is effective only under certain conditions and requires the use of special "mission profiles".
In my years of LIDAR enforcement use, if used correctly, I never had an instance where the unit would not clock a moving motor vehicle at a range obviously in excess of the driver's perception of my presence. Typically, with an average effective clocking range around 2,000 feet, and a max range sometimes in excess of 3,000 feet (both depending on ambient conditions), by the time oncoming traffic saw me and reacted, I was either shooting targets several vehicles and a thousand or more feet behind them, or I had the unit put away and was just waiting for them to arrive so I could invite them to have a chat, or I had radioed their description to the next chase car waiting over the hill or around the corner and I had gone back to shooting other targets. On the other hand, if I made myself highly visible, it was either because I wanted traffic to see me and slow down (school or construction zones, for example) or I was engaged in other unrelated activity and didn't care.
A significant portion of the people I stopped for speeding over the years had RADAR or LIDAR detectors in use at the time. There are many ways around the detectors for the trained and experienced operator, and in some circumstances the presence of a detector can even be advantageous to the enforcer. In my experience, your chance of receiving a warning for speeding is significantly reduced, if not eliminated, if a detector is in use. Also, the use of detection devices by the violator is typically noted on the citation for the benefit of the court (many LEOs, prosecutors, judges, and magistrates feel that the use of a detector shows at least an intentional disregard of the law, if not prior intent). And yes, there are sometimes other ways for the enforcer to tell if a detector is in use besides actually seeing the unit.
As for the common LIDAR urban legends, not having a front license plate on your vehicle makes no difference on the signal return or range (ditto for special "anti-laser" front license plate covers, etc.), but if it's one of the thirty-five (ish) states that require a front plate, "failure to display" does give the enforcement one more potential reason to stop you (this obviously does not apply to motorcycles). Having your headlights on also makes no difference to the LIDAR unit. Like sound or radio, light has a frequency, and automotive lights are a different frequency than the LIDAR signal and are therefore disregarded by the unit. In my experience, the only factors that sometimes reduced the effective range of the LIDAR unit were out of the vehicle operator's control, such as ambient weather conditions (heavy rain, for example) or the amount of frontal area presented by the target. Less perpendicular frontal area on the target typically returns less energy to the LIDAR unit, but this is a relatively small factor in typical enforcement use. Excessive cosine between the unit and target will also weaken the signal return exponentially and the indicated speed, if any, will err in favor of the target, which is why LIDAR and RADAR operators are trained to avoid it.
The best way to avoid enforcement action is to obey the law, or at least be within "tolerance" given road, traffic, and weather conditions, and don't combine violations. In other words, if you are a few mph's over, you calmly and safely correct the discrepancy ASAP, and you're not committing any other violation at the time (unsafe following distance, failure to signal turn or lane change, equipment or registration violations, etc.), your chances of being stopped go down significantly. However, if your speed is "out of tolerance" for road, traffic, and weather conditions (typically more than 10 -15% over the posted limit under ideal conditions, although they don't have to allow any tolerance at all over the posted limit), regardless of what else you may or may not be doing at the time, you stand a good chance of being invited to the side of the road for a chat.
Be safe.
