Funny, I asked the same question and it didn't go down too well. The is no "grey area" regarding emulation. It's illegal, full stop. Nintendo.com even have a page on their site stating their position on that. We "legalise" it to ourselves buy buying copies of the actual full game, but essentially it is illegal, and certainly more than the offending leaked demo. There's no loophole.
We can't "buy" the early copy of Doom 3 and after all, its a 6-month old, incomplete, buggy and hard to get demo - NOT a full version even. This is a 3 (incomplete) map DEMO.
id will lose zero money on it, get a huge chunk of free publicity (Not to mention coincidentally people will rush to upgrade their PC's before release - meaning more sales of the game - which will do manufacturers of GFX cards etc a lot of good), and apparently aren't the ones hitting sites after all. I could list around a half-dozen easy found sites which have it on their front page, free for all to see, freely asking for id to email them if they want it gone. So far, id haven't shown the slightest real concern to any of them and they've been around for a day or two at least. If the producers who are behind the game don't care (lets face it, they probably leaked it in the first place), why should we?
And incidentally, we weren't pointing the way for people to find it. Don't need to. We were talking FPS rates and config...
Legal is legal, illegal is illegal. The only difference with software is the harm it could cause. In the case of N64 ROM'z, we negate the harm by spending the money we do. In the case of an alpha-level demo, who gets harmed? Who loses money?
BUT - who gains potential sales and publicity for the final product, and in the end will profit from it?
I rest my case. Or something.