i saw this on the news the other night. i think it sounds like a good idea. so i looked it up on the net, heres a brief description from tyhe web site.
http://www.autodot-usa.com/ "The DataDot Technology is a high quality substrate, the size of a grain of sand, laser etched with a PIN number or VIN number. The DataDot makes it possible to easily authenticate your vehicles identity, without the need to look up a secondary database or obtain forensic examination. Up to 10,000 DataDots are applied across your vehicles major parts, using a special clear drying adhesive with a UV tracer. The large quantity of DataDots, marking your vehicle, becomes a major deterrent to potential thieves. The DataDots also provide simple verification by authorities, which are further enhanced by the UV tracer in the adhesive."