Yes, I believe so. I mean, no one can prevent other people from engaging in a large transaction with a vendor that exceeds what the vendor has spent on building up his reputation, but I think we can make sure all the information is available for nodes to make an informed decision, and not make it profitable for the vendor to attempt to cheat.
Eg. in the user interface of the application talking this hypothetical decentralized anonymous marketplace protocol, a warning could pop up if you're trying to place an order with a vendor that has open orders for a value of, say, 50% of what he has burned in total.
If nodes who begin a transaction with a vendor simply publish their unsigned multisig transactions -- signed by the vendor in a way that doesn't make the transaction valid, but enables other nodes to cryptographically prove that the vendor has accepted this transaction and that it is open -- to the network (and I see no reason why they wouldn't want to), we can know the total number of outstanding orders for a vendor, and the their total value. Along with information on how much a vendor has burned in connection with other trades, we can figure out whether we would put the vendor in a position where he could profit financially from running off with the money, were we to place out order.
But remember, an escrow service is involved. The vendor would have to convince the escrow service to sign the unsigned multisig transaction (open order) so the vendor gets the money. Although the vendor can just promise a cutback to the escrow service. But if we make sure that the total value of all open orders doesn't exceed a tempting amount for the vendor, we can at least make the dishonest behavior of a vendor unprofitable.