I wonder why mine works just fine then? My review OS is W7 and is an unactivated copy. I have full functionality of the OS outside of the watermark on the bottom of the screen (maybe I don't get updates?). I do receive a popup that says I may be a victim of counterfeiting and it takes away my wallpaper, but then I put it back on (when I need the wallpaper in the screenshot). When I re-image it, I get all the updates through SP1. This OS has been stood up for months on various HDDs and motherboards. Its W7 Pro 64bit if that matters.
After thinking about it, my XP was like that. Its been so long since I was on XP, even for benching. I vaguely recall XP and having to re-image it after 30 days when I benched, but, not with W7. I have never had that OS activated on the review system in years. Not sure about 8 as I skipped that. Sorry for the blanket statement, I know though W7, at least for me, doesn't lock me out.
EDIT: Now, I enter a key upon install... it is a legit key but it is tied to another system, and now, Windows 10. Prior to that, I ran one activated (my daily driver) and the same key inactivated. both W7. Perhaps because I enter a key, is that why I still have 'full' functionality?