If I was on my bike and another bike pulled up alongside me and flipped me off, I'd know what it was all about and consider myself to have made another friend.
If I'm on my bike and a car driver flips me off there's no way I can be sure that it's because of the sickers on my bike. I'm not going to get all physical on someone because of it, though, and it wouldn't make me mad 'cos really what it is to get upset about? If I then saw that they had an ADV sticker on their car (I have one on mine) I'd understand what it was about and appreciate the gesture. If they didn't have the sticker on the car, or I didn't see it I'd be unsure, but that's all.
To the OP - that sure is a funny story! Thanks!
Ride Report: Canada North to South 2008 here
Drive Report: Ice Road Trucking 2005-2011 here