[...] all parties to a transaction agreed to use a particular person as escrow.
No. Read the
Coinbet sig thread. No mention of participants' pay depending on the escrow not running away. I expect to receive the wages promised me, unless the company employing me declares bankruptcy. Both the gambling site & the totally real ugaise cloud mining/web wallet/MLM operations claim to be doing just fine.
In the case of Coinbet, it would be coinbet that is responsible for making the payments as they would be the one who received the benefit of the signature advertising. The campaign manager is merely an employee