Actually, although you may feel that you have a right to know who, you don't and naming him could open Eleuthria to libel charges. The only right you have is to choose to use, or not use, this pool. All this person did, in reality, was distort the Luck figures and receive some compensation that in hindsight might not have been deserved. but playing a loop hole, if it was intentional, is not illegal. Most likely this person wasn't aware of the problem.
What if it turns out that USB Block Erupters are the problem? do you think people running them will stop? individually, they are undetectable, too small. but, there are enough people running them to have an impact. Think, how many of them there are in the world. All we can do is sit back and let the pool operaters do their thing and hopefully they will give us some insight as to what hardware is the problem and how to fix it.
I'm waiting on a response once they believe they've fixed it (which they seem to have done, they tested a software patch on another pool and did solve a block). My understanding is that the group of users were running custom gear, but I have asked them for more detail (chip manufacturer, software kits if any). They did NOT have problems until the difficulty passed 4.2b, and that was proven by looking at their test runs when they used to mine on Eligius. They moved to BTC Guild in early April because they had fewer connection issues with our servers.
It has been 4 weeks since they started mining on BTC Guild. So unless there are other, yet unknown, hardware issues, only the last 1 month of luck (at most) is the fault of this group of miners. And up until recently, there was NOT enough data to rule out variance.
EDIT: People can point out that action was taken after they started non-stop posting in the thread, and they can continue to do that all they want. People will always try to assume a causality when something happens, ignoring the fact that action was going to be taken whether they said a word or not if something was actually broken. I began talking other pool operators and asking if they had noticed any miners with unusual luck since we were all trending downward. We started discussing possible causes (hardware releases, the 32-bit overflow point, etc.). But at the time we had nothing firm, and there was not enough data to rule out "luck happens". That was only 3 weeks into this group starting to mine on BTC Guild, and that was the first point where the 1-month luck interval began to take a significant dive. Even at that point it was NOT clear if it was simple variance. I've been running this pool for over 3 years now, and big swings were not unusual.