As an avid cyclist I won't wear it, not because I'm stubborn but because by wearing it (as many seem to do) it panders to the idea that vulnerable road users have to be all glowing with an assortment of colours so that the poor motorist who bombs along in a ton plus of metal (proven to kill and maim in the tens of thousands every year) can get to where they are going a few seconds/minutes quicker.
Even the government themselves (actually under labour) are adept at victim blaming when it comes to these things rolling out scare tactic 'safety' programmes in schools to make kids wear hi-vis and blame them if they get hit rather than the errant motorist, the whole thing is sickening.
I put decently bright lights on for urban riding at night and poor visibility conditions, have a few reflective strips on my cycling gear (you can't avoid it totally) I've being hit (from behind at a roundabout) once in the late evening yet hit 3 times during the day, people look but don't see, ask the police force how many officers get killed or injured whilst wearing it due to being struck by a motor vehicle!
Hi vis needs a light source for one thing so during the day is worse than useless.
It's funny how we in the UK even allow black cars to be sold (the most popular by far at almost a 1/4 of new cars sold) or grey or dark green etc, motor vehicles driven by the public are not hewn in day glo colours either so why should the vulnerable who have a right to be on the road (remember motor vehicle drivers are privileged by license)?
it's the motors that do pretty much all the damage to life so they should be taking the greatest portion of care by far, in most Western European countries they have 'Strict Liability' laws, that assumes that the fault is with that at the top the tree (the motor vehcle) unless proven otherwise (in its simplest terms). This pushes the onus for road safety massively on the metal box drivers as it rightly should be
Imagine your son/daughter, mother father being killed because of some bulldust excuse of 'the sun was in my eyes', 'I didn't see them until the last second' (as they sped around a blind bend), another good one of late is the 'temporary blackout', all common ready made excuse for car drivers who run over and main & kill people.
Blame the victims, that's what I say