I would think it could be quite risky to try to get a court to tell people not to use the software you gave them... the court might reasonably, actually consider the question of "why" -- as in "who is harmed"?
In the court of public opinion perhaps, it would be a public relations problem. But in a court of law, that question is entirely meaningless when it comes to intellectual property. "But it doesn't hurt them" is not an affirmative defense in intellectual property cases.
Its also important to note the distinction between a court enforcing a EULA, and ruling whether its valid. This is very critical if subtle distinction. A court could rule the EULA valid, in which case it could enforce its terms upon any recipient of the software. Conversely, it could rule the EULA invalid
and still order the return or destruction of the software. The reason is this. If the court rules the EULA is either not valid or unenforceable, there would then be the separate question of whether there now exists any right for the user to possess the software. Dissolving the EULA doesn't mean you can hop and skip away and do whatever you want. It can mean the court rules that NCSoft can't enforce its terms on you, but also that without it there is no longer a legal right to the software, and you'd have to destroy it. You don't get to just have it just because to took it. The court could rule that without a valid contract both parties must walk away surrendering any temporary rights they were granted because of the contract that is now dissolved.
I don't think most people who believe they can challenge EULAs fully appreciate that legal point. The EULA is the reason you're allowed to have the software in the first place. Destroying it legally doesn't mean you get to keep the software automatically. If you invalidate the contract upon which you took out the mortgage for your house, guess what? You don't get to keep the money and the house. You get to become homeless when the contract dissolves and the money you got only due to that contract must be returned.
The reason we get to keep the CoH client and play with it isn't because the EULA is unenforceable or because of any legal argument: its because its entirely not worth NCSoft's time to try to get back every single copy of it, and because nothing would be worth the bad press if they tried. But I guarantee you if there was a self-destruct button that was capable of destroying every copy of the client and they pushed it, none of us would have any legal right to challenge that.