Visited the British Music Fair in Birmingham UK last week. Met a guy who runs an instrument insurance company who, as part of the policy, will mount an identification chip in a secret location on your guitar, harp,violin...any instrument. Doesn't enable a tracking device, but it does establish pretty conclusive ownership if a stolen instrument is subsequently offered for sale. A quick scan reveals all.
            A bit of info & not very subtle bump!
                                                 Nigel P. :)