I came across this article in the NT Times earlier today and found it strange enough to blog about. Some businesses in Europe have found a novel way to use DNA for fighting crime. Instead of taking DNA samples from robbers, the businesses set up devices that spray synthetic DNA onto the robber while also alerting the police. Although in theory the DNA can be made unique for each business (so it could serve as a marker), the idea is to scare robbers away from committing burglaries in the first place (since the DNA could be seen under a special light and so identify them). So far police say it's working, although they don't have hard evidence to support their anecdotes. A DNA "crayon" can also be used to mark goods to identify them in case they're ever stolen.
One of the interesting points made in this article is that this spray may be effective because of the "mystique" surrounding DNA. I wonder if the overall scientific literacy of a society would affect the effectiveness of this spray. Would it matter if another chemical was used instead, like the security devices on expensive clothing that explode and leave stains if they're not removed properly? On the other hand, if there was a society where a few people had the technical knowledge to handle DNA but most of the population knew very little about it, would that increase DNA's mystique? I think in that case, you'd be venturing into the realm of Clark's third law. I suppose it's easier to spray DNA onto someone than a RFID tag--though perhaps in a society where people have electronic implants or always, always carry cell phones, it'll be easy enough to track people without the extra DNA tag.