Encryption isnt a panacea thats one of the P2P myths and a dangerous on at that. Look at the fasttrack network they have encryption yet the RIAA was still able to figure out all it needed to sue them. Either way who would stop the riaa from downloading and modifying an open source program to track users.

The reasons why gnutella hasnt been sued is that its open which is the biggest reason, no log-ons or user names, it has many more uses than just file sharing, and search is really not that much different than any search engine out there.

Gnutella is alot like the web so if the RIAA wants to shut it down they will have to do it like they do on the web and go after indivdual users which will be a PR nightmare and the cost too high. Which it will be very unlikely they will do that. They will most likely try other ways like DRM and etc.