The theory is certainly good, but the remaining difficulty is that someone (other than the thief) has to (1) have a scanner, and (2) know that an item might be chipped, and (3) put the two together and actually scan the item and look up the registration number that's found.

The chip is useful as proof of identification but that generally will only come up when you've got the thief in front of the judge (magistrate). The chip won't be much help in finding a lost item that could be in lots of unknown places. All of the usual "take good care of your stuff" rules still must be applied.

The same chips have been in fairly widespread use for tagging animals for several decades. We've had three tagged pets lost, all of which were tagged, and none have ever been identified.

Nearly all veterinarians will have scanners, and are "supposed to" scan any animal that comes in "with questionable identity" but none that I've heard of actually bother to do so, unless the person bringing the animal in asks them to do it.

Disposal of dead animals (road kill?) in normal "trash" is prohibited by law, and some of the disposal service people are quite conscientious about refusing to pick them up and/or referring them to other places for proper disposal. For "non-commercial" animals, the only proper disposal in my area is at the "Humane Society¹," and they claim to have a "policy" of scanning any pet-like animals, dead or alive - but they almost never do.

¹ Used here as the generic place where people take lost animals - not necessarily the same name used elsewhere and not necessarily a place associated with either "official channels" or any animal protection organization.

The chips have been so seldom used for "hardware" that I doubt that the majority of "hock shops" - or even more traditional "dealers" - even have a scanner.

The local cop that I asked about it (in the robbery division) said "I think they have one in the autopsy lab."

The chips are a very good idea, and should be considered as a way to positively identify anything if you'd go to court over it, but we've found them of rather marginal helpfulness for our small family members, where they're very commonly used. (But all our current pets do carry chips, since it's still possible we just haven't encountered the situation where they work.)

So far as I've heard, the is no national registry of chip numbers, and we've found the record keeping for pet chip registrations "sloppy" (being generous) but if you can include that a chip is in a lost item, and provide the chip number from your own records in your police report, it might be helpful - after they use your clear photo of the item and it's "visibly identifiable features and markings" to find it.

John