Interesting. Win8 Pro Retail from Technet silently activated Windows with my product key without any input from me. Y'know, clicking the "Windows needs to be activated" icon that pops up on Win7. I think that is part of the new hammer down on piracy policy that MS has implemented with Win8.
Yeah, its a bummer for somebody like me who installs a VM, tests something and then simply blows away the VM. In the past, I simply just installed without a key and never had to activate since my machines only lasted a few hours to a few days at most.
Oh well, I will just use the "enterprise" copy of the software for this type of testing purposes. With 5 keys for Pro and multiple activates per key, I shouldn't have any issues.