It's not just the license for the format (besides even without the license .ogg > .mp3 ), but the fact that they'd need to pay a ton of cash just to have a single track of <insert famous artist>.Turns2Ashes said:This is why the tracks in UT2004 are in OGG format as opposed to MP3. OGG is free for all purposes, whereas they'd have to pay the guy that created MP3s if they used them. Check out HL2's legal fine print and you'll see it says something about MP3's being copyrighted and licensed. Dumbasses.
They're far better of using 'nameless' artists or even better would be people that actually know how to write music for movies/games instead of even trying to match any famous artist to their game.