I missed that comment.
el_rika, it's not an excuse. Insomniac and Naughty Dog have some pretty advanced streaming engines going on, but when a completely new environment needs to be loaded and it's the first time you go there, some loading is necessary.
In Uncharted, they've done it in a quite interesting way, and you can test this by the various ways you can go into a level. For instance, if you boot up the game and start in a new chapter, then if you skip the intro to that chapter (which you can), you'll see a loading screen.
If you finish the previous chapter and enter that same chapter, that loading screen will sometimes be shorter, because it already streamed some parts of the level and keeps some bits of the game in memory (or in the HD cache it uses).
You can see the exact way in which this works in the document that Naughty Dog released on their own website during GDC, detailing almost the whole engine, including the BluRay-HDD-RAM streaming mechanism they used.
I wonder, by the way, if there are really benefits to realtime rendered non-interactive cutscenes other than saving some space on the disc, which often isn't that big an issue on the PS3 as it is on other consoles for obvious reasons. I think getting the framerate of those cutscenes with decent framerates, etc., is typically more work for the developer and more work for the artist. If you make them interactive however, that's a wholly different story of course.