Trouble with a alser detector is, apart from due to become illegal (TT to comment on this...), by the time it goes off you've been stung. The lasers, which are still used by the plods who stand on the road side, are very accurate and the beams diffuse very little, hence it is hard/impossible to detect without taking a direct hit.
Plus if the plod sees you hit the anchors as he points his gun at you he may not be overly impressed.