I know a few things about the problems the engineers had with developing the Kustom lasers. I hear they had problems with the noise floor of sunlight overpowering the signal. The optics are very expensive and heavy. The calibration sheets we had at the time showed the unit operated at 50MHz, which is easy to generate with any LED.
Just like any speed measuring device, I'd imagine the designs quickly got smart to evasion. Its no engineering feat to detect unexpected signals, including sudden bursts of noise. If an officer catches someone with one of these, that person is going to be the celebrity of law enforcement.