The courts would likely decide whether the prizes being won have value based upon the letter and spirit of the law, prior legal precedent, and reasoned argument. The EULA is designed to protect online services against civil lawsuits, similar to a sign in a parking lot that reads: Cars left over 1 hour will be towed or not responsible for lost or stolen valuables. It does not necessarily have any legal standing in a criminal case.
While the fact that Cryptic discourages the buying and selling of these items on the aftermarket might be considered, at the same time, a court could not ignore the fact that these items clearly do have a measure of real value, as they have been bought and sold for hundreds of American dollars.
So yes, the EULA is pretty good at protecting Cryptic if someone gets their accounts terminated by violating the terms of the EULA. However, it does not necessarily have any legal standing in terms of questions of State and Federal law.
An example would be a somewhat analogous situation. Let us say I open a Casino. It operates exactly like a regular Casino except you cannot change your chips back into money. Since it is for entertainment purposes only and you cannot get anything of value from the chips, I assert that it is not gambling. It is no different than paying a quarter play a gambling arcade game. I state clearly on a big sign at the entrance that by entering the establishment, customers agree not to buy or sell chips and agree that chips are the property of my business, whether or not they have won them.
Somehow though, there ends up being a huge aftermarket for these chips. Since they cost real money, people pay real money for them. Some people spend hundreds of dollars buying these chips from other players, which they then use to play at my casino. Now, do you really think my disclaimer would protect my business? Probably not. The courts are almost certainly going to consider the fact that these chips are worth a lot of money on the aftermarket.
Of course, Casino gambling is an old game and I am sure the courts have seen the vast majority of schemes. MMO's are relatively new and there is probably very little case law covering instances like this.
To further support Sakarak....courts across the globe have already decided legal issues in regards to the determinations of virtual items...there is small but significant legal precedence for this issue....2 of the big court cases I remember reading are in regards to Second -Life i believe (? memory is rusty...its finals time)
PS Sakarak...Awesome letter (to the Cali AG you posted