I have always wondered why men of the Federal Road Safety Corps always play the oppotunists. It is either they hide after a bend, in traffics during the morning rush hour, at a speed bum or near a police check-point. Are their main concern catching people unawares or ensuring that traffic laws are obeyed? And you hardly see them in the night. Are traffic laws not broken after dark?

I've always observed they stay at spots where it will be almost impossible to manoeuvre on sighting them, you'd just have to drive straight into them

Because they have to generate revenue. Police hide in developed countries too, so that they can easily catch traffic offenders using speed radars. They issue tickets and demerits on license when one is caught..(revenue generation and to keep bad drivers off the road).
A friend was caught running 90km on a 50km/hr zone. There was construction going on at the zone, hence his fine was doubled. He was given an $800 fine plus mandatory court appearance.

They also sometimes hide inside their unmarked/ghost cars behind buildings, road curves and under bridges.