If your DVDs conform to the standard they should play on all DVD players/software, right?
Which may be technically illegal since it uses decss (although, according to wiki, the one case that came to trial over decss resulted in an aquital)...
But yes, I don't see how this will help anyone. Users will just use VLC/decss and not pay the license fee, so the DVD industry loses money; MS's OS will be crippled and open the door to Apple ads about PCs not playing DVDs and general ridicule and the consumer has to go to extra effort to play their discs.
Wow, you guys are so scared of Apple. Apple removed floppy discs and didn't worry about ads saying "OMG, Macs can't read floppy discs!!". Apple removed optical drives altogether from MacBook Airs, its #1 laptop seller, and didn't worry about "OMG, MacBook Airs can't read optical discs!!!" ads.
Besides that, what's it matter anyway? I recall the Apple "I'm a Mac, I'm a PC" ad that claimed that PCs couldn't import pictures taken by Japanese digital cameras. Totally false, but it didn't stop Apple from running the ad anyway. Apple's going to run whatever ads they want to run regardless. Competitors should stop cowering in their boots about what Apple's going to do.
Lastly, Apple's main product isn't the Mac, and you don't see many Mac ads anymore. Their main product is iPad/iPhone, which can't play DVDs (and can't to a whole LOT of stuff, but you don't see Apple scared to ship the product worrying about ads against the things that iPad cannot do).