I can't see how this is enforceable, TBH. It's quite legitimate to transfer large amounts of non copyright data across the internet, perhaps encrypted. Are ISPs going to be storing every byte transferred to or from every subscriber, cracking the encryption and then determining if it's legitimate? That's a lot of work. What's in it for them? My quess is that they'll nail a few obvious offenders in high profile cases to show what a great job they're doing and ignore 99.9% of what goes on. Pretty much the current status quo.
P2P is used for a lot of legitimate purposes, such as distributing open source software, even commercial software and updates, so there'll be uproar if they just block it. Illegal transfers of copyright material will go encrypted so they'll never keep up with it, and it'll make it harder than it currently is to detect.
I'm not so sure the music industry are as hard done by as they make out. It's always been necessary to copy their products for personal use on other mediums, and they have chosen to turn a blind eye as the internet has crept up and allowed more widespread sharing than the borrowing and taping of CDs and LPs that used to go on.
Their reluctant response has been to allow online purchase of lame downloads with huge amounts of compression and crippled with DRM so they're less flexible than a CD or, indeed, an illegal rip of a CD at decent quality, yet the cost for such downloads is in the same order of magnitude as a CD.
Personally, I don't think music habits have changed. People listen to a small amount of "copied from my mates" albums, just like they used to in the days of cassette, and if something's decent they'll buy it on CD and use ripped copies on an MP3 player when convenient. A CD is something tangible for your money, at least. Listen to it at home with reasonable sound quality, copy it to another format for use in an MP3 player, and it's something you can be proud to collect, unlike a collection of DRM-crippled 128kbit files on your PC.
Anyone who can think even for a minute that this kind of enforcement is plausible has no understanding of the nature of the internet whatsoever, IMHO.
Kevin