I noticed the same thing, and even mentioned it to another member I was talking to at the time it was going on.. I found it rather strange.
I bet none of you have noticed this:
The last photo on the left, of the MacBook Pro, under the "Photos, music, and videos. Be VIP of your TV." category on THIS page. Do you notice Toy Story 3 is already artworked and in their iTunes library? ^^
Yeah they aren't even the full movies that are played back in the demo. It is obviously just a clip, which is evidenced by the fact that it starts at a random point in the movie rather than the beginning (and never prompts to resume playback).
Same thing happens in nearly every demo of this type. It's all very planned and staged, no surprise unless it's the first time you've watched a keynote.