Phased Radar behaves differently to door openers DD.

CW Door openers pretty much spatter radar everywhere, and it can actually be pretty strong.
Thus why our falses seem to remain.

Where as phased LOW powered radars like the Redflex and Gatso 24 have beams that are focused in an area about the size of half a sheet of A4 paper.
They are bloody hard to detect, and what ever has been "improved" to lower false detection has indirectly caused issues with detection.