While certainly not impossible, all the work that would go into faking this exploit simply isn't worth the reward of a cheap trolling.
Well, he gave himself like 3 days (minimum) to work up the video.
Really, this would be cool if it's true.
It's always good to be at least a little skeptical no matter what evidence is shown, though.
I understand the exploit's out there. There's 31 who have a certain exploit (not to say someone else couldn't have made another one or just come to the same conclusion as them) and if any of them are either part of these 4 "horsemen" of accidentally let the exploit get leaked, it doesn't seem IMpossible that this is legit.
What's shown here, though, is an icon installed into the menu. That takes a bit more than just an exploit (how long on the Wii was it just disk based exploits until they came out with the HBC?). Again, this doesn't mean it's not true but IF it's true it would mean it is a pretty nice accomplishment.
If they didn't actually install anything, this could also be just using an exploit to patch some channel's title, splash screen and icon in RAM so that it just LOOKS like they installed a channel (but they had to cut the video off before Wind Waker suddenly loaded after the splash screens, for example) This would be something that the average user couldn't do and wouldn't be possible at all without an genuine exploit of some sort BUT would not be QUITE what it appears (I'm reminded of neimod's "homebrew channel" that he just patched a title which WAS legit hacking, just not what it looked like)
And then, of course, there's always the possibility of smoke and mirrors with mere video playback, moving his finger in slowly so you can't be sure when it's silhouette actually touches the screen, just timing it right, using a link in the browser or a number of other little tricks that could make it LOOK like it's something that it's not
So it would be nice. It could be. It's definitely not impossible ... but to be on the safe side, it's not to the point I'd be betting any money on it yet. Call me a fence sitter for now.