That said, I think that hi-viz works to bring more attention and I suspect a different attitude toward you as an unidentified motorcyclist. I think that people have all kinds of different conceptions and emotions when they see you ride past. Some people seem to hate "sport bikes" and "loud Harleys" and I think if they see you go past in ATGATT in your hi-viz, I believe they are more likely to view you favorably, like you are a responsible person rather than "one of those other a*holes" on a bike. Even if you actually are one.
I will affirm this statement as well. I have noticed when I am wearing less gear, I get treated by some motorists as an annoyance - tailgating me, cutting me off, etc. In my full gear, I get a little bigger berth from most. Or so I think.
I think the problem we are having with the poll is a definition of "work". Does hi-viz prevent *all* accidents caused by an unseen motorcyclist? Of course not. Does it prevent *half*? Studies would suggest no. However, at what point does a minor action on your part (wearing a vest) become a good idea for potentially life-saving benefits? At what point does spending $150 on a modulator become a good idea?
Nothing you can do can prevent all of the accidents all of the time. No amount of gear you wear can prevent all injuries all of the time. Motorcycling is dangerous. However, being more visible, like wearing good gear and riding safely, can reduce your risk of catastrophe. Studies have supported these ideas. Although a terrible indicator with N=1, my personal experience has supported these ideas.
Wearing hi-viz increases the chances that somebody that wouldn't have seen you dressed in black does see you now. Let's be pessimistic and say it only does that 1 time out of 500,000. My personal choice - I'm OK with the giggles and funny looks for that 1 out of 500,000.
Finishing off this long post, I do think it's a personal choice. I used to be much more opinionated about gear vs. no gear, hi-viz, etc. Then I realized nobody likes a jerk from either end of the spectrum

I completely understand why people don't want to dress up like a road construction worker or Power Ranger when they ride, and I appreciate their choice to do so. I simply ask they appreciate mine.