In the UK, we are less than a week away from the new £1 coin coming into circulation, which has been billed as 'the most high-tech coin in the world'.
In an effort to reduce counterfeit, they have had a mysterious new technology integrated into their design, code named iSiS (Integrated Secure Identification Systems). There seems to be some deliberate ambiguity around the nature of this technology: undoubtedly as an attempt to unnerve potential counterfeiters, who can't counteract what they don't know about.
Some people are speculating that the 'top secret security' of the iSiS coins is in-fact an RFID or other microchip; which not only explains how 'thousands of coins [can] be scanned and verified in a matter of seconds', but among skeptics leads to concerns about them being used as tracking devices.
IF this were the case (and I'm certifiably not trying to persuade anyone that it is), what would be the legality of UK security services being able to use these coins to track citizens? If the coins were capable of this, wouldn't they be under an obligation to publicly disclose this?