There's one other situation, when there is a business where nobody trusts the brokers. The diamond industry is a good example. Where does a diamond come from?

There's one other situation, when there is a business where nobody trusts the brokers. The diamond industry is a good example. Where does a diamond come from? Sellers don't want to know when buying from shady brokers and obfuscating or altering the origin is extremely valuable and hard to detect, so brokers have huge incentives to cheat and thus the database can't be centralized.