I could be wrong (I'm traveling and so can't check for sure) but if I remember correctly, I think Warner Bros. uses secondary audio for their PiP commentary. The "in-movie experience" on both 300 and BATMAN BEGINS are the ones that come to mind. Maybe V FOR VENDETTA as well. Again, I could be wrong and can't check but I hope this helps!
12/10/10 at 10:07pm