Have never seen that before, either. I will be good to remember when I get tired of waving when the bikes are out in force. The donor bike group do not usually expect a wave from anyone but another of their own around here, so I usually oblige with no wave. In Ca. in the 70's and 80's, we usually waved with an upright closed fist. In NJ now it is more like a low five. What is your sign? TR