When asked why this suit was different from Sony's case, the counsel representing the RIAA and the MPAA said that Sony had no way to prevent unauthorized copying on VCRs, but that Morpheus and Grokster, the two file sharing networks named in the suit, could apply the filters.
This is not technically true. Sony could have placed a file listing every piece of copyrighted work in existence on every VHS device and made it impossible to copy them. However this would have made the product economically impossible. But that's what the RIAA is now asking the file sharers to do now. And we don’t think a court will impose a sanction on file sharing networks that makes it economically infeasible to carry out their business.
The more and more I read about online file sharing, the more it seems to that that the RIAA and the MPAA are fighting what can only be a losing battle. The only way to enforce copyright law to the degree they are asking is to let slip the dogs of a draconian police state in which only authenticated users would be allowed to connect to the network.