After consultation directly with both ARCA and NASDAQ OMX, here are some facts. Neither one of these exchanges formally accept stop orders. Therefore, the answer to the key question is no. There would be no advantage. Stop order liability will never be the legal responsibility of these exchanges. That is not to say that if they clearly fumbled the order, the exchanges here would not rectify it in some manner. They probably would rectify it in most cases. But there is no formal legal liability here as to stop orders. However, when routing an order to NASDAQ OMX, you route the stop orders to INET. INET IS part of the NASDAQ organization umbrella. This is different that in most situations where the stop route is not part of the buy route entity. If the stop order is recognized by INET and there is a failure of execution, that would probably be more favorable to the trader in a worse case scenario than if a 3rd party platform server failed to execute the stop order. But ascertaining what that difference is between the two is unquantifiable.