If you don't trust your escrow agent, you shouldn't be using them as an escrow agent.
The idea behind escrow is to use someone you trust as an intermediary in a transaction with someone you don't trust.
I think the issue he was talking about, is what if I sent the coins to escrow, they sent the cash, and instead of sending me cash, they sent me some newspaper clippings that are roughly the same weight as the cash would be. Then I would be saying that I didn't recieve the money, and the person buying the Bitcoins with have tracking information that said delivered. So the escrow agent would have to decide who gets the Bitcoin.