Overestimating what they see?
Hi-Viz isn't all that hi viz after dark. Once dusk settles in, it's not much better than gray and you're relying more on the retroreflective components. Riding to Portland one year, I was being followed by some friends who were trailering their bike. They noted that the hi-viz became nearly invisible after dark. My riding buddy was wearing a Sea-bak reflective vest and was infinitely more visible than I was.
I am suspicious about drivers seeing my 3M stuff from the front because of headlight glare. I use a Sea-bak vest after dark now, and I'd be surprised if it makes a different at all from the front.