A reputation system will be needed because as the identity is known to the other party (bank details) there will follow by itself a reputation system if we dont install it. Users would start to blacklist scammers in forums or make false accusations.
But its another challenge to build a solid reputation system.
Hey k99
Have you had an opportunity to take a look at bitcoin-otc "Web of Trust". It has been running smoothly for some time so it's something it's worth checking. This web of trust has supported trades without collaterals, so I guess it's going to be good enough for your enhanced system that includes collaterals and game-theory to enforce that traders stick to the initial contract.