They are? I have to disgree with you there,whenever I've driven the car,I've never had to be close to a cyclist before I saw them. Maybe you need an eyetest?
Ha ha. Seriously, stand at one end of a long street in daylight and try to spot a cyclist in a) normal clothes and b) fluorescent clothes in amongst the heaving masses. Which do you see first? (This isn't the same as 'which is safer' because drivers ought to be able to see and avoid a cyclist when within, say, 20 metres of them.
When in hole, stop digging... Motorists really ought to be watching the majority of the streetscape which isn't other motor vehicles, not only the other motorists which can drive into them.
"Ought" being the operative word here. The thing is, do they?
I don't do hi-viz but I do keep a white/reflective mesh vest in my pannier that I whip out to use if I happen to find myself out riding at night with dark clothes on.
Shouldn't be necessary as I'm very well lit, but there you go.
But at night, your lights and, especially, your reflectors, should make you pretty clear. I would question whether its actually during the day that you need the hi viz (???)
Wear a seat belt in a car? Because most of the time I feel safer, especially when at high speed. But then again I hate my modern car boing at me becasue I'm driver at 10 mph in the car park or