Review copies of Electronic Arts's Kingdoms of Amalur: Reckoning are starting to reach critics, who have made a surprising collective discovery: an insert containing a code to download a "House of Valor" content pack featuring "seven additional single player quests."

EA has confirmed to Ars Technica that this downloadable content will be included free with all new copies of the game, including digital copies purchased on the PC through Origin, Steam, or other services. Players who would rather purchase a pre-owned copy, however, will presumably have to pay an additional fee if they want to access to this portion of the game.

Charging used game players for such an "Online Pass" is nothing new in the game industry, of course. But implementing an Online Pass in the single-player Kingdoms of Amalur represents a continuing tumble down a slippery slope for the entire game industry.

A subtle redefinition

EA experimented with locking out used game purchasers from some limited downloadable content with Mass Effect 2's Cerberus Network, but the company first embraced the idea of charging for Online Passes on a large scale in mid-2010, rolling out "Project Ten Dollar" to charge for online gameplay and features in its myriad sports games. In launching that program, EA justified itself by saying it had "made a significant investment to offer the most immersive online experience available," adding that it "want[s] to reserve EA Sports online services for people who pay EA to access them."

In other words, EA was saying that used game purchasers were actively costing it money in the form of continuing server costs, which the company deserved to recoup. Publishers including THQ, Warner Bros., Ubisoft, and Sony have used similar justifications in copying the system for their own online games.

Here's the thing, though—Kingdoms of Amalur is an exclusively single-player game. There are no multiplayer servers for used players to theoretically exploit as freeloaders. The original, stated justification for the Online Pass has disappeared, but, for some reason, the Online Pass itself is sticking around in games like Amalur.

The Arkham City defense

EA declined an opportunity to comment on its reasoning for expanding its Online Pass system from online modes to single-player quests. The company would do well to come up with a better defense than Warner Bros., which pulled a similar stunt by charging used purchasers for a set of Catwoman missions in last year's single-player Batman: Arkham City.

The company's official (and rather weak) justification for nickel-and-diming used gamers? "Playing as Catwoman is not required to complete the game."

When pressed by Wired.com to expand on that official defense, Arkham City director Sefton Hill emphasized that the Online Pass content is less than 10 percent of the entire game. But this kind of argument represents an extremely slippery slope that could lead to a further redefinition of what it means to buy a used game.

The slippery slope

Look how the concept has slipped already. Online Passes, which started as a way to pay for continuing online operating costs, are now used to lock used players out of small portions of the single-player game. As time goes on, what's to stop publishers from expanding the concept further, locking ever larger portions of a game behind a downloadable pass? Will we soon see a game that prevents used purchasers from finishing the single-player quest unless they pay to download a required mission? Where's the cut-off?

Used game fans would be justifiably irate if a publisher abruptly used Online Passes to completely hobble pre-owned copies of its games (or just abruptly stopped used games from working altogether). But by slowly and subtly moving the goalposts for what's "acceptable" to block from used game buyers, publishers like EA may be trying to acclimate customers to the idea that they shouldn't expect a used game to offer them a complete experience, or that they shouldn't be interested in the ability to buy used at all (hello, digital downloads).

If that's so, publishers may be betting that the easiest way to blunt the impact of used games might not be a technological fix, but rather a simple, methodical redefenition of the very idea of what a used game is.