I don't want to be a wet blanket, but I'm guessing that once the novelty wears off, most people will return to their habit of taking the escalator.<p>I realize that this probably isn't a permanent installation, but someone did this in a more permanent fashion at a building near me, and people spent a lot of time playing on the stairs when they first went in, but now most people are back to using the elevator.
As many reasons as there are <i>not</i> to do this (some of which are pointed out in the comments), it's hard to argue with 66%. Sure, it's novel so that's part of it, but I think the basic idea of making things fun to get people to do them is great.<p>On another note, the easiest thing to do in that case would be to remove the escalator. ;)