I wouldn't be surprised if many pirates are, though.
Look at all the software that exists to help pirate stuff, the dozens of seedbox companies, the hundreds of trackers.
I'm doubtful it would have a big impact. The knowledgeable would slap a VPN on their PC or buy a seedbox. The less technical would wait for Deluge or Transmission to add a VPN panel to their settings screen.
I'm fairly certain things would go back to normal pretty quickly.