He had just mentioned custom clients in general but it all comes together at some point. Painhertz, I don't think you understand that there is no reliable way to simply detect if a client has had modifications made to it.
If I am a gold seller running hundreds to thousands of bots at a time do you really think I am running 1000 instances of the normal client? No, I am running a completely stripped down null client which means no graphics, no interface and no client side security if said client even utilizes that at all. If million dollar companies don't have a reliable method to detect these changes, I don't know what you expect Jorb and Loftar to do in this case.
Which is why I said the security needs to come from within and as far as anything server side related that goes beyond manual policing I don't know about that so I don't feel confident in commenting on it.