Over here in Ireland we currently use a small number of automated fixed position Gatsos, which work by radar. If you get caught by one of these you are a fool or from out of town.
If you are travelling nationwide, the roving police traps are always Laser. For these you can be caught very easily, they only need seconds to lock on and they use a narrow beam.
Using a laser scrambler is frowned on and illegal. They can impound your vehicle. If you are the only car on the road and you jam their device, they ARE going to stop you and search your car.
I see a scope for a device which is currently not catered by any of the speed detector manufacturers. Say you have a radar/laser detector which can jam laser. If you are travelling below the legal speed limit you do not need this device to be jamming police laser guns.
So how about somebody inventing software that can pair this device with an accurate GPS unit? The GPS unit monitors the location and speed of your vehicle. Assume the GPS unit has a database of all active speed limit boundaries [they do have over here] .
If your vehicle is travelling below the speed limit the GPS could be programmed to deactivate the jammer, though not the detector. If the vehicle is travelling a user resettable value above the limit [2 mph, 5 mph, whatever you decide], then the GPS unit turns on the jammer.
That would be a device I would be interested in having, although I must admit, I don't speed much. I just don't like points on my license, and I don't like the sneaky places they tend to catch people.
Joe