By the way, although the weather issue probably sinks the original idea anyway, I should probably explain what the goal was in the first place, in case there's anything that can be salvaged from it.
The first thing to point out is that the message isn't for NCsoft itself - or rather, the message being delivered is not the same as the one on the banner. We don't need to tell NCsoft how we feel - by this point, they're very well aware. The banner itself would be for the surrounding onlookers - and because it's flashy, it would have that much better chance of being picked up by the news, in addition to people looking up "savecoh" hashtag on Twitter or googling it. The location is important as well, with a symbolic value - the fact that someone came to your proverbial doorstep to deliver a message of displeasure, yet being completely out of your reach or influence, is going to carry a much greater impact than simply reading about it on the internet.