How do you escrow goods which cannot be validated?
That Ethereum address containing UTRUST tokens was a good example.
The seller and buyer cannot trust the escrow with both the private key and the public address. The escrow cannot check whether the private key unlocks the public address.
Do not complicate things Try to read the whitepaper and you will be enlightened.
"Enlighten me then"

But seriously read white paper and you will know everything that you should know
Alice sells the private key of her Ethereum wallet to Bob. Bob pays through UTRUST. Alice is notified that the money is in escrow and sends the private key to Bob. Bob claims the key does not work. Alice opens a dispute.
Tell me how the UTRUST Mediator resolves this transaction.
Alice still has a copy of the private key and she proofs Bob that the key works by transferring the ETH to another ETH wallet, before Bob can scam her. Alice decides that Bob is a scammer and does not trade with Bob anymore. Bob just lost his money to Utrust.
But in case Bob already moved the ETH before he claims the key does not work, well Alice is scammed.
I guess some products just shouldnt be sold, like private keys
