I consider myself somewhat repuable.
I think you missed TangibleCryptography's point. You are the one selling the non-reversible currency. It is you that would have the concern about whose funds from Dwolla you are accepting. If your counterparty were to claim that fraud occurred after the funds are traded with you, Dwolla would reverse the payment or try to claw back the funds from your bank account if you withdrew. But your counterparty would already have redeemed the MTGUSD code and you'ld be out the money. Dealing with a reputable counterparty lessens that risk.