I remember a case a couple of years ago where the county coroner put someones death down to the fact that some bright spark in Suffolk CC had decided that if there was ANY dwelling within about 100 yards of the road it had to be a 30 limit-extending for several 100 yards either side of any dwellings. The coroner made the point that drivers got so frustrated by unnecessary limits that they would overtake as soon as there was any possibility. The overall result was that there had been a significant increase in head on collisions-mostly fatals-whereas in the past most accidents were at junctions and survivable. Of course the road safely nazi's will say it is the drivers fault and they should all keep in line like good little sheep.
i don't think it's entrapment. It's a simple case of stupidity. Having dealt with councils at a planning level in my job I have come to the conclusion that they seem to be full of f*ckwits and people who wouldn't last properly in a commercial environment. Common sense...the lack of it...seems to be endemic.