^...definitely counts!...as nice, but misguided....that could cause an accident. Hope she wasn't driving. A phone number would be better. I'll bet that, flashed on a piece of paper held to the window, would be easier to remember than a license plate number, you think?
I'm about to go out on the bike right now. Doubt there'll be any driver's that nice, but them just following the rules of the road and keeping an eye out for vulnerable road users will be enough.