If you're thinking of grabbing the update, think again. According to Major Nelson using the leaked update disables Xbox Live on a console until November 19, the actual release of NXE. With Gears of War 2 just around the corner, you wouldn't want to take your console off the grid would you? While no reported bans have been handed down since the leak showed up it isn't hard to imagine Microsoft could take you offline for good. You've been warned.
[Update: Major Nelson wrote on his twitter, "If you get your hands on NXE and you are NOT in the Preview Program. You won't be allowed on LIVE." We will not be linking any websites with information or links to download the NXE - hence the replacement of Major Nelson from the original source in this story. Users who leave links to such content in the comments will have them swiftly removed.]