Maybe local cycling clubs could print these up and hand them out at shopping centres on Saturday mornings (in our club gear, of course) as well as talking with families/motorists about why.
Meeting cyclists in a different, less pressurised situation to usual might help to increase understanding between drivers and riders. We’re not just anonymous people in funny looking tight clothes, we’re human beings too.
I’d gladly do this…and let’s face it, everyone loves a free bumper sticker.
(And yeah, yeah I know the hard core bike haters won’t be interested – but that’s not the point. They’ll never change, but plenty of others might.)