Tiny RFID tags

The BBC has an article about recent innovations in the miniaturization of RFID technology. The image at the top of the article is particularly astounding: these RFID chips are smaller than the width of a human hair. The very image suggests the possibilty of putting RFID tags in someone's hair gel and using the tags to track that person. That statement no doubt sounds paranoid, and maybe it is. But the fact that these things are getting so small means that surreptitiously distributing these devices is getting easier.