They'd have to introduce this at the ISP level, similar to how Time Warner Cable sends cease and desist letters to people if they detect you're torrenting their or their partners' content (a friend of mine got one for HBO shows. They required him to run a script on his computer verifying the file was deleted. WTF?!)
But the thing is, people who get massive amounts of content this way don't BT to their machines! Most use seedboxes and rsync back to their home machines. They're only going to get the people who are not big in the game (relatively).
Plus, once you identify, the next phase may be blocking at the ISP level. Then you get into censorship, network neutrality, etc.
Fuck everything about this.