I think it was on a thread here once?

There was a recent case in this area where a womans cat went missing and several years later after continuous searching, found that their neighbours had taken the cat with them when they moved. They got a letter to say the cat was safe and well but the company/vet wouldn't release the information on where the cat was because it was confidential information?
So basically the microchip showed it was their cat but the information was confidential because the cat wasn't theirs anymore?? Surely if the cat had a microchip with the original owners name etc on it then it has to be legally theirs? I just don't get it!

I know a dog has to wear a tag for legal reasons but I microchip in case the tag gets lost (which does happen) so I can still get my dog back. But it seems to me from the above case that it's pointless?