Placer Sheriff hides along side business walls and other obscure places. Part of this route is 25mph zone. I have seen them park back from the street, and stand behind trees or phone poles and zap you, then radio to another deputy. They also do this very early in the mornings, even on Sundays when there is little traffic. It is one of the most oppressive applications of traffic enforcement anywhere around.
Sometimes they do park in plain sight however.