it's close, but no. "Fartkontrol" would be directly translated to "speed control", but "speed trap" would be a more accurate translation. So when we say "pas på fartkontrol" we mean "watch out for speed traps".
The purpose of the cameras in the first place is to prevent speeding not to fine. The absence of cameras in places does not mean that there are no cameras, however. There are also portable (by minivans and SUV's) cameras that keep changing place after all.
But, why are you surprised? Don't Fartkontrol signs do the same thing, I mean warning about speed traps? Unless you mean something else by speed traps other than cameras and similar!
We have a 10% error margin allowed by the law btw. So in 120kmps speed limit places we can go up to 132kmph max and the cameras don't catch us. One millimeter per hour over that and the camera flashes.
Actually we don't even have permanent placed cameras anywhere. So those signs would not do much good anyway.
We only use these minivans and police officers with speed guns. They never stand the same place more than 1 day.
So "fartkontrol" being ether a van with a cam or the police standing behind a bush or similar and catches people via speed guns.
we ofcause have plenty of these signs that reminds us that speed is dangerous.
We also have some "signs" that shows our speed. so if we drive too fast some lights blink. they do not send tickets. they just warn us of our speed. I guess this is our version of your countrys speed traps with warning signs.