As Patrick Naughton's trial gets underway Tuesday in Los Angeles, his attorneys will test a new Internet-related defence strategy -- namely that their client was role playing in the fantasy world of chat rooms and never really believed he was going to meet up with a girl who was only 13. Naughton, 34, a Silicon Valley Wunderkind who lead Java development at Sun Microsystems before heading Disney's Internet ventures, is charged with crossing state lines in an attempt to have sex with a minor. Naughton was nabbed in September after allegedly arranging a meeting at the Santa Monica pier with an FBI agent masquerading as a young girl in a chat room. Agents arrested Naughton shortly after he met with a woman FBI agent posing as the girl. Naughton also is charged with using the Internet to try to solicit sex with a minor and possessing child pornography. Now his defence will try to show that he really didn't think he was meeting up with a 13-year-old, but rather someone who liked to play one -- a novel defence strategy, according to both legal experts and those involved in the case. "This is all relatively new territory," Bruce Margolin, Naughton's attorney said. "We're breaking new ground." When the trial gets under way with jury selection on Tuesday, Margolin said he'll try to find Internet-savvy people to serve on the panel. "We'd like to have people who are really savvy," he said. "Savvy people would know what these chat rooms are like." The defence was hoping to introduce testimony from an expert witness who would say that as many as two-thirds of all visitors to Internet chat rooms fake their age or gender. However, Federal Judge Edward Rafeedie clamped down on that evidence during a pretrial hearing, saying he was hesitant to allow the fantasy testimony because it didn't seem relevant. "The defendant isn't on trial for what he said, he's on trial for what he did," the judge said at the hearing. In a later ruling on the issue, Rafeedie said he would only allow expert testimony on the role playing issue if Naughton takes the stand and says he believes he chatted with people who regularly faked their identities. Defence attorneys wouldn't comment on plans to put Naughton on the stand except to say that most people expect that he will testify. The expert that defence attorneys hope to use is Kimberly Young, a University of Pittsburgh researcher and "cyberpsychologist" who wrote "Caught in the Net," a book about Internet addiction. She also runs the site Netaddiction and has testified as an expert witness about Internet-related behaviour. The Internet adds a new twist to efforts to reel in paedophilia and child pornography. While it makes it easier for law enforcement agents posing as young children to bust suspects, it also allows for large-scale distribution of child pornography and gives paedophiles easier access to kids. What's more, Internet chat rooms muddy the water because people aren't always who they say they are. After all, it's hard to argue that a person showing up at an elementary school with a lollipop to talk to children doesn't know he or she is dealing with minors. But a person chatting online with someone claiming to be a 23-year-old woman may really be talking to a 70-year-old man. Jennifer Granick, a defence attorney who's worked for high-profile cybercrime defendants such as Kevin Poulsen, said the defence will have to convince jurors that chat rooms have new rules. "The defence's task is to introduce to the jury the world of the Internet chat room, to introduce that what goes on in an Internet chat room isn't the same as what goes on in the real world," Granick said. "The chat room by its very nature lends itself to fantasy." Elayne Savage, who researches online relationships and has written a book on the topic, called the defence strategy "creative". "Why couldn't it be believable, because in cyberspace there's so much role-playing going on," said Savage. Savage also said there could have been something in the FBI agent's tone during the pair's chat room conversations that encouraged the role-playing. "He was on the receiving end of somebody who was role-playing, so there may be an element of role playing in the air," she said. Still, Savage said Naughton crossed a line if he intended to meet a young girl. Susan Brenner, a cybercrime expert and law professor at the University of Dayton School of Law, called the Naughton lawyers' defence strategy "logical". "But saying it's a logical defence doesn't mean it's going to work," Brenner said. According to an affidavit from the FBI agent posing as the child, Naughton gave his real number and address. Therefore, prosecutors said during a pretrial hearing, Naughton was not role-playing -- a point they likely bring up in trial. The judge also cited that fact in his ruling on whether Young can testify. "The defendant apparently did not assume another identity while on the Internet, so her testimony is not relevant to explain his behaviour," Rafeedie wrote. Brenner said the role-playing defence could hinge on the make-up of the people who frequent the "dad&daughtersex" chat room, where Naughton was caught. If the chat room usually attracts adults and no children, that could bolster the role-playing defence, she said. Brenner said it would be much harder to evoke the role-playing defence in a case where someone was talking with kids in a chat room devoted to dinosaurs or Pokemon. "If you're in one of those chat rooms, there's a high probability you know you're dealing with a minor," Brenner said. What do you think? Tell the Mailroom . And read what others have said.