That doesn't sound right to me. Scammy exchanges run away with the balances people carry at them, right? That seems very different (and much more lucrative and viable) than a retail storefront changing overnight from reputable practices to theft. Obviously the former is a real problem and a big threat, although it has little to do with reputation systems. The latter doesn't sound like that big of a threat. It seems like the cost to establishing a retail storefront with a solid reputation is not worth the quick payout from theft. In fact, if you have the initial capital and business acumen to run a stable retail storefront, it's probably more profitable and less risky to just keep doing that.