How would you prove to a blockchain that a particular serial number really is owned by you, or was lost, or all the other things that can happen that don’t occu

How would you prove to a blockchain that a particular serial number really is owned by you, or was lost, or all the other things that can happen that don’t occur on the blockchain? Aren’t you sort of back to needing the cooperation of lots of different entities globally, and some kind of authority equivalent to the third party database maintainer to ensure the data makes sense?