I've seen all the chatter on all the forums: Paizo, EnWorld, even ICE regarding this. Its the knee jerk reaction of trying to stop piracy in the 90's which didn't work. By pulling off all legal/downloadable D&D material - which includes 1e - 4e material, WotC is only guaranteeing pirating of their material.
Its unstoppable. Plus unless the distributors of PH 2, will only get a slap on the wrist, as it must be proven that they've actually profited from distributing their material, there is almost no case for punitive damages.
No, this action only forments pirate activity, not stop it. It's foolish, but then I have lost most of my respect for Hasbro/WotC, long ago anyway.