UPDATE: A Bethesda representative has told VideoGamer.com that the PS4 and Xbox One versions of The Elder Scrolls Online do not require a CD key to play after all, and that the publisher's original forum post was incorrect.
"The physical console version of The Elder Scrolls Online: Tamriel Unlimited does not require a one-time game code, as with any other boxed PS4 / Xbox One game only the game disc is needed for verification," Bethesda said in a statement this afternoon. "Any previous statements counter to this were incorrect."
Players will be able to trade the game in, the representative added.
ORIGINAL STORY: The PS4 and Xbox One versions of The Elder Scrolls Online will require players to register a CD key included in the box to access the game, meaning pre-owned versions won't work if the key has already been redeemed.
Bethesda confirmed the requirement on the game's official forums, explaining that console players "will need a unique game registration code in order to play the game, and used copies will not be eligible to receive a key if the code has already been redeemed.
"It works the same way as the PC version in that the code included in the box is to activate your ESOTU account and the discs are for installation purposes. If you own the disc but don't have a key, you'll be able to install the game and reach the login screen, but you won't be able to log in and access the game without an active ESOTU account."
While unusual for a console release, the requirement isn't hugely surprising considering the game's subscription-free online nature.
The PC version of The Elder Scrolls Online transitioned to a subscription-free model in March, having previously required a monthly subscription fee.
It remains unclear, however, whether multiple users will be able to share the CD key to play the game on the same console, or whether they'll each be required to purchase their own copy. VideoGamer.com has contacted a Bethesda representative for further clarification.
The Elder Scrolls Online: Tamriel Unlimited launches on PS4 and Xbox One on June 9.
Source: forums.elderscrollsonline.com (via neogaf.com)