Helping the pirates? How will the MPAA, and RIAA track users by IP address then? Seems like they might be helping the pirates out.
There's no technical reason why an ISP can't log traffic through a NAT gateway. Record the time the connection was initiated along with the port numbers on each end and it would be easy enough to attribute that connection to a specific user. MPAA's investigators would simply need to provide port numbers along with IP addresses.
Exactly. They'll be forced to do what other providers do (in other countries where they really have no more IPv4 addresses)... extensive logging. I don't think anyone has thought about how much work this really is. Or how much it will cost to keep this massive amount of data for the terms they are required by law to keep it.
(I did netflow collection at a Tier3 ISP a decade ago. Compressed, that was nearly 1GB per day. That was in a world of IDSL, SDSL, and T1's. I don't want to think about how much traffic that is today.)