Actually you're really quite off. The laws and the knowledge of
the laws (learnt when you are getting your license) are to deter
people from speeding. The TPs are there to enforce the laws. Simple,
really.
I understand your point. But the truth is people speed and I
admit, I do so sometimes as well. Of course what I stated will
never happen at all in Sg.
Just that my point is lets say a TP hides in some obscure place
and catches a whole load of speeders. Ok, but at that time, those
speeders do not know that there's a TP there and will still
just speed to whereve they are going, thereby being a
possible danger to other motorists, until he reaches his
destination. By the time he gets the letter from the TP, the
"damage" has already been done. Its like you shit your pants
already then you go find toilet.
However, if the TP is standing at some more obvious location
like an overhead bridge, then those speeding can see him and may
take action to slow down their vehicle, thereby driving within the
speed limit. The presence of the TP will, in this case, deter
speeding on the spot. If people still blur blur speed then just too
bad for them.