The Electronic Frontier Foundation and its ideological allies argue that this kind of license is invalid and unenforceable because of a "fair use" right to reverse engineer. I'm not so sure about that, though.
The real question should be: Would a reasonable person expect to find that kind of restriction in a software license agreement? If the answer is yes, it's a legal contract. (Courts have properly ruled that unexpected fine print in a standard contract, such as a no-alcohol-at-all clause in a car rental agreement, is unenforceable.)
Nobody is forcing Blizzard customers to click "I agree." In fact, they can return the software for a full refund if they don't like the fine print. Or they can continue the reverse-engineering process without the benefit of having the software installed normally--a more difficult task, but not impossible.
Don't be surprised if the 8th Circuit chooses tried-and-true contract law over the hacker ethic.
This is wrong on so many levels, and yet possibly correct. The fact that you might expect to find a restriction doesn't make it reasonable. The idea of reverse engineering software without installing it is a bit silly. We ought to have the right to take things apart. However, this is something that probably can only be done with legislation. We'll see how this case sorts out.
