Meanwhile, Barry, as a biker - can you tell me what the problem would be to wear one anyway. A lot of bikers on another forum (France related) which I frequent are very unhappy about this. Please explain to Mme 4 wheels what the problem is.
I think the basic reason is the type of people who ride bikes don't like being told what to do.
As to there effectiveness, if the SMIDSY's can't see a bike with it's headlight on, then a hi-viz will make little difference.
Also there is some who think the less loose clothing there is to catch on something while you are sliding down the road the better thats why you should never wear a chain looped over your shoulder.
Much more dangerous is the new rule on daylight running lights on cars, at the moment we stand out (headlights on). When all cars have to have running lights we again merge into the general background light clutter.
Pushbikes are another matter.