An EFF article posted by Cindy Cohn includes:
EFF and others have long warned that copyright claims could become an altar on which personal privacy is sacrificed. Now the RIAA wants your ISP to voluntarily wield the knife, and there's no telling what else the RIAA might ask for once this cut has been made.
Canadians should remember that it is our stronger Privacy legislation, which requires that the copyright holder provide a minimal level of evidence of infringing activity before the court will allow the disclosure of private information.