I think it also has to do with clearing firms, software being utilized and the types of adjustments Firms want to make to the trading accounts. I think Penson, regardless of how well capitalized you are would require changes in overall risk to go through them as of right now if you are using any of their sponsored MPID's to directly access any exchange through many of their supported platforms, as would others for some of their supported platforms. Some platforms have the ability to set overall Firm limits and allow Firms to monitor and adjust limits within those for their traders, while others don't have that capability. In those instances clearing firms will require setting to be changed on their end. For GSEC, Redi is the only platform that is really used wide scale (and it's owned by GSEC) so I'm sure some of these issues wouldnt matter. For other clearing firms and trading firms that are able to and use multiple platforms, these issues of changed risk setting procedures will be more prevalent.
The biggest concern is with sponsored access. This is a direct connection to the exchange through a co-located server, with direct market access sponsored by the member. Before , these had very little protection. A black box connected this way could cause a lot of damage in the market. It looks like the SEC took those concerns and broadened them. The goal after the flash crash is to protect the market structure. They will do what they have to in order to make the market safer. This is the concern of the Prime Broker. I don't think it will effect most traders. The problem is the Firms had very little time to comply and a lot of work to do.
Wat could b done by the affected firms? They dont control sec decision so wat can they do to protect their interest?