It just makes it harder to prosecute. Doesn't void such cases that use IP. From the last paragraph of your link:
"While Judge Baker’s decision will make it harder for copyright owners and their organizations to take a “guilty until proven innocent” approach, there’s another lesson here too. You need to secure your Wi-Fi connection. Sure, anyone piggy-backing on your Wi-Fi connection is probably just using it to check their e-mail, but there’s that one time in a thousand where they may be doing some illegal and it will be you, not them, explaining to a court that it wasn’t you who downloaded am illegal copy of The Hurt Locker."
And this judge thinks differently:
"During the course of the year many of the defendants in the Hurt Locker case who were already subpoenaed have claimed innocence. However, last week Judge Howell decided to dismiss all 119 motions to dismiss, quash, and for protective orders en masse, adding them to the pool of targets."