Ali, if you want one of these stickers just get onto ebay. I think I found them in the 'automotive' secton. Couple of bucks each and they seem to stay on pretty good. Huge selection and lots of very funny ones. Easy to lose a few hours reading them all.
I have the 'caution blonde' warning on one of my old boards & it is still in pretty good nick after 2 years of daily use.
I only found the 'not drunk' one recently and I couldn't believe that someone in sticker world knew me so well!!!!