This is a true story which happened on the M1 a short while ago:
A police officer had found a perfect hiding place for watching for speeding motorists and one day, the officer was amazed when everyone was under the speed limit, so he investigated and found the problem.
Ten year old Dennis Porter was standing on the side of the road with a huge hand painted sign which said “Radar Trap Ahead.” A little more investigative work led the officer to the boy’s accomplice, another boy about 100 yards beyond the radar trap with a sign reading “Tips” and a bucket at his feet, full of change.