Supporting a ruling delivered by a lower court last April, the 9th US Circuit Court of Appeals in Los Angeles in August announced that the file-sharing firms cannot be held responsible for the use to which their services are put, so long as they are not directly able to stop the copyright infringing acts in question.

"The (record labels and film industry) urge a re-examination in the law in the light of what they believe to be the proper public policy. Doubtless taking that step would satisfy the copyright owners' immediate economic aims. However, it would also alter general copyright law in profound ways with unknown consequences outside the present context," the court explained in its verdict.

Speaking to the IDG news service on Monday with regard to the Supreme Court Petition filed jointly with the Recording Industry Association of America (RIAA), an MPAA spokesman announced that:

"We believe that the liability, the secondary liability that these companies have avoided by building their companies in such a way to get around the law is something that needs to be thought about and revised."

The Supreme Court is likely to announce in November whether it will hear the case, unless the peer-to-peer firms file for an extension.