As we said on the show, Blizzard is making sure that this is an event that everyone feels -- in the past, you could avoid most of the world events just by staying out of certain areas or certain zones. But at the same time, that made some players feel it wasn't immersive enough -- why have a world event if it doesn't affect the whole world? And so this one does -- no matter what level you are or where you play, whether you got eaten by a zombie or downed Tenris Mirkblood, you know that the Lich King is coming. And some folks, who play the game casually or at a low level, just don't care.
Update: Well that's timely. In between the time this post was written and planned to go live, Blizzard has decided to cure the plague. Considering that things moved so fast this weekend, that seems premature, but we'll have to see how the event plays out -- Blizzard is of course saying that it's not because of the vocal minority speaking out against the zombie gameplay, but we'll have to see what happens next.