If the stop for the cutting tool is in the right place, it should at least not harm the disc as far as the data stored on it is concerned. If a player clamps onto the disc's hub properly, though, I can't imagine the perfection of the outer radius making it easier for the laser to track. Seems like another tweak that tries to cloak itself in scientific plausibility that don't stand up well to actual technical scrutiny. I'd call it another "placebo" tweak. ("Hey, I just shaved the edges off my DVD, see how much better the ones and zeros stored there look now!")