James Cicconi, AT&T’s senior vice president for external & legal affairs, set off a firestorm last week after The New York Times reported that he said his company was working with the Motion Picture Association of America and the Recording Industry Association of America to implement a digital-fingerprinting scheme and would detect and filter out copyrighted material from its network.

Cicconi made his remarks during a panel discussion with representatives from Microsoft, NBC Universal and several digital-filtering companies at last week’s Consumer Electronics Show. Most of the discussion revolved around whether carriers should start taking a more active role at sifting for and blocking copyrighted content at the network level.

“We are very interested in a technology-based solution and we think a network-based solution is the optimal way to approach this,” said Cicconi, according to Times. “We recognize we are not there yet but there are a lot of promising technologies. But we are having an open discussion with a number of content companies, including NBC Universal, to try to explore various technologies that are out there.”

Of course, AT&T hasn’t yet released any specific details of what plans it will or will not consider. When asked to elaborate on the content of the company’s remarks, the company has only released a statement saying that “this is not about the vast majority of customers who consume content online legally” but is rather “about combating illegal activity.”

But several experts in telecommunications law have already warned that any elaborate attempt to filter traffic by AT&T could cause the carrier legal headaches. For example, as Columbia Law School Professor Tim Wu noted this week, carriers currently bear no legal responsibility for the legality of the content that goes through their networks. Thus, if someone with an AT&T subscription spends all day illegally Bit Torrenting movies, the fault lies with the individual pirate and not the carrier.

But in order to keep their legal immunity from piracy charges, carriers must meet certain requirements. According to a 1998 law that deals with carrier liability for illegal digital communications (17 U.S.C. § 512), carriers can maintain their liability as long as “the transmission [of copyrighted content] is carried out through an automatic technical process without selection of the material by the service provider” or if “the material is transmitted through the system or network without modification of its content.” According to Wu, “once AT&T gets in the business of picking and choosing what content travels over its network” then “it runs a serious risk of losing its all-important immunity.” Wu acknowledges that the law as written “is not entirely clear,” but adds that AT&T could likely still have to deal with legal headaches, as any packet-filtering system might turn AT&T into “the world’s largest target for copyright infringement lawsuits.”