P2P File Sharing

In his article for NYT (Should Online Scofflaws Be Denied Web Access?) Eric Pfanner discusses  the idea of blocking the internet connection for poeople who abuse the system thru P2P platforms. I don't see how it would be possible, aside from the fact if it is the proper way to deal with the problem......
Those 'pirates' can always use open  internet access on e.g. campuses or internet caffees... They can also open new accounts with internet providers or even steal the access from ignorant neighbors, who don't protect their wireless connections (....yes they still exist    :)   )
P2P platforms are created for the purpose of sharing information. Some people use them in noble way e.g.  to share a marketing presentation, that is "too big to email".... Other people use them for sharing their music, movie or software files which is basicly piracy.....
File sharing done by companies is usually(to my knowledge) legal sharing of some files (e.g.TV networks offering some of their shows online), thta was introduced to eiyher generate addition income (e.g. from ads) or to offset illegal downloads....
On the other hand, P2P (peer-to-peer) sharing is a wild wild west, full of illegal activities. 'Peers' share music, videos, software or even books files.....