Nice idea, but it gets old fast. It started back when I owned Corvettes; they all had the "save the wave" thing going on. The motorcyclists do it as well. During bike week, you'd be waving all day. Seemed dangerous to me to be riding the motorcycle with one hand.
If a Mustang owner waved at me, it would be difficult to wave back with the tinted windows being closed most of the time in Florida
. I'd try, but may not make it in time for the other driver to see.