There was a gentleman who's story I read on another forum that was hit from behind by an inattentive motorist while still wearing his vest, and rather well lit with blinkies etc, a couple years ago. He was hospitalized for about a week and off his bike for several months. That he survived was good, but just doing all you can is sometimes not enough... but I'd rather do all I can to see and be seen than leave stuff up to chance.