1. Not every State requires officers to be scientific experts on the operation of the Lidar, only the practical operation.
2. You would be hard pressed to find even the cheapest current model lidar painting more than a 3' target at 1000'.
3. A good officer is taking more than one reading and/or tracking the violator vehichle for a long enough to establish a speed.
4. Can't speak for others...but fishing for speeders is good enough that I don't bother with any violators that I'm not 100% on.
5. Not every State cares about distance. Depending on traffic, weather, and road layout, and equipment being used...it is super easy to get people at 1,500-2,000 feet...and easy to get people at 2,500-3,000 feet if you have a magnified scope and steady (rest) the lidar on the edge of your window. That said, I prefer 1,000-1,200 feet for my final reading...but it is nothing to identify people at 2,000 feet, hit them again around 1,500, and then take final readings around the 1,000-1,200 foot mark. It you were speeding at 2,000...speeding at 1,500...and still speeding at 1,200...it is a pretty safe bet that you are speeding :-)