Again, I don't think a blockchain is a fundamentally wrong thing here, I just don't think it's needed. It all depends on your threat model. With a decent policy you could run this on a standard database and even if the front line verifiers are corrupt ,if the DB admins are not then they can't cover it up. If you don't trust the DB admins you can pawn the trust off to Amazon, and if you don't trust Amazon or the company , but do trust whoever the miners are then a blockchain is needed We've had car deeds etc. for years without a blockchain. Maybe it would be more transparent and auditable with one but I agree with Rusty's final conclusion that for most things its not necessary. Also: if the blockchain is 100% private to Rolex they could trivially 51% attack it, or rather 100% attack it.