I use an opposite approach. I have two bikes, one a carbon cross/trek-style and one was the cheapest I could find as a city bike. The carbon one I'd like to keep, so I put stickers "Ferrari" everywhere on the cheap one. For quick value judgement on which bike to steal I hope the brand name beats the carbon frame. I had some people standing around and admiring my "Ferrari" in the public already, so it seems to be working somewhat...