Howdy Morgwen.
I completely realize that Napster and Gnutella are completely different things. I completely realize the Gnutella network can't simply be unplugged. I completely realize that fire is hot. I competely realize I shouldn't bathe with a plugged-in toaster. Etc etc...
I merely mentioned Napster to illustrate a point - be too specific in your mechanism that can be used for distributing copyrighted material, and you'll give reason for believing the tool's primary purpose is, well, distributing copyrighted material.
When (notice I didn't say if) the RIAA decides to come after Gnutella, they're going to go after visible figures to attack. And what are the visible figures in the Gnutella world? The Gnutella clients.
I'd just hate to see the authors of a program that we all find useful be subject to any sort of legal harassment, that's all. Sure, we can always move on to another Gnutella client, and the network will survive, but that doesn't do Xolox's authors any good, eh?