An interesting idea.
Sometimes I feel like people pass me because they assume bike=slow. I was coming down Middle Road toward Etna the other day and probably averaging 30 mph. This woman kept pulling up close behind me and finally got around on right hand bend. She then had to slam on the brakes going into the next left hand bend because of her speed. And where was she in such a rush to reach? The Eat n' Park parking lot at the bottom of the hill. We reached it essentially at the same time.
But she didn't honk, didn't yell at me, didn't gesture at me or anything. I just think she felt like a bicyle meant she was being slowed down and she never even looked to see how fast we were going.
Of course, no one would ever register why those numbers on your back were changing....