Can anyone think of any possible reason why a disc should lock out switching audio or subtitle tracks while a movie is playing? I was going through the alien quadrilogy discs, and there were a couple points where I couldn't make out some of the dialogue and wanted to switch on the subtitles. Usually I can just use the subtitle button on the remote to cycle through the tracks, but on these discs the only way to enable the subtitles is to go to the menu, change the option, and then resume the film. It seems to me that this is an option that would have to be deliberately set, and I really can't figure out why you'd want to do this. I've noticed this happening with audio tracks as well, and I suppose that this could be locked out to keep people from accidentally accessing a DTS track when they don't have the hardware for it, but this is really the only reason I can think of. Can anyone else come up with a better reason for the subtitle switching lockout?