Check out this article: The reading is relevant to a point and also addresses issues similar.
It is on digital products purchased on Amazon Kindle, and Amazon's unilateral decision to delete according to its EULA.
Did a quick read and honestly what I got from it is that the case against Blizzard for altering an item is shaky, but it could also be valid.
Correct me if I'm wrong, but it seem as though the legality of the issue would be the classification of an item in Diablo 3. Do consumer rights hold true for a digital good? What laws is the digital good pursuant to?
"Courts in New York and California have taken the lead by recognizing various forms of digital property as convertible." (Quoted from the same article up top)
Fortunately, it seems as though consumer rights for the people residing in those states would fall under the consumer rights laws from tangible goods to digital goods.
One quote I enjoyed reading was this "Elaborating on the practical realities of virtual documents, the court also concluded that it is not a document’s or idea’s physical manifestation that determines its worth, but the value of its content. " (The value of a virtual good)
In RMAH scenario, the values of items on RMAH lost value or increased value overnight by the changes from 1.0.3. (eg. 1100 dps one-hander becoming an 850 dps-one hander)
There are some key points that seems substantial enough for litigation. Simple matter is that there is a real $ value associated to digital products (RMAH even recommends a selling price). Similarly to the Amazon Kindle case, RMAH consumers are buying licenses, instead of buying the whole product.
I'm studying for the LSAT, so I don't have any legal experience other than interning as a paralegal. Let me know what you all think.