Knock on wood, knock on wood, knock on wood...
I've not been honked at by a motorist yet...but the dualie pickumup trucks and muddy Pontiac TransAms that come up behind me love to roar by as though the idiots behind the wheel have got something special in their foot pressing the accelerator...
Besides, I'm 220#, 6' 5" and geeked out as an Old F*rt riding the biggest bike they've probably ever seen. My seat is up at the same height as most of their roofs so what are they going to do, mess wid' de ol' guy?
I DO like the idea of a paste-on card. But in composing your message, remember that if someone is too stupid to know the law or drive correctly, they are unlikely to be able to read sentences longer than twelve words or words longer than eight letters...