The fact that Microsoft's own processes aren't rigorous enough to have prevented this test code leaking into their live environment is VERY scary.
Microsoft should come out and say exactly what the test patch actually effects/does, not just say that they are removing it. Its already in the wild and already effected public systems so therefore WAY too late for Microsoft to live in denial about it. I'm surprised that The Reg allowed themselves to be brushed off with corporate hyperbole instead of pushing Microsoft for these details, but I'm not even slightly surprised that Microsoft are still doing their usual "you don''t need to know what we are actually doing to your property" coverup instead of doing the real professional/correct thing.
It just boggles my mind how evern large companies and so-called 'professional' IT managers can see this stuff happening then still choose to buy more Microsoft products to run their entire businesses on.