That, though, is exactly what happened on New York's Long Island a couple of weeks ago, provoking a storm of national controversy. Not that it was primarily the idea of the local police. Rather, it was set up by the producers of a truecrime show on Rupert Murdoch's Fox television network, who thought it would be just the thing to up the ratings in a key "sweeps" week, when advertisers pay particularly close attention to audience ratings before they negotiate their rates for the following few months.

Lauren Nelson, the Miss America who went along with the scheme, insists she believes wholeheartedly in the cause of getting would-be sex offenders off the streets. But she was also marketed to death by Fox executives, who plainly saw the set-up's entertainment value every bit as much as its utility as a law enforcement exercise.

"You've seen her in a bikini, " read the teasing home page of the hit programme, America's Most Wanted. "You've seen her in an evening gown. You've never seen her like this." As the programme documented, four men who came to meet her at a house on Long Island were arrested on the spot . . . with the cameras rolling. Another seven men who had exchanged explicit online messages with her were arrested a few days later.

While some police officials and media commentators expressed satisfaction with the outcome, a growing backlash posed serious questions about the wisdom of the whole enterprise. "I think the whole thing is a disgrace and an embarrassment to law enforcement, " criminal law professor Richard Klein told Newsday, the main Long Island paper. "To set people up and the way that it's done for ratings on TV shows, it's just really disgraceful, a waste of time and shameful in so many ways."

John Powers, a defence lawyer one of whose clients was caught up in the sting despite suffering debilitating psychiatric problems, concurred. "The police department, with the aid of Miss America, John Walsh and the Fox network, created this crime where it didn't exist, " he told the paper. So strong was the backlash that last week numerous media reports suggested Nelson was getting cold feet about testifying in court about her exploits.

On Friday, however, she was back on track, and even denied there had ever been any hesitation. "Until yesterday at noon, I had not been asked to testify, " she told the Associated Press. "I started out with this operation to put online predators behind bars and off the streets, and I'm going to see that operation through to the end. If that means me testifying or being part of this criminal case in any way, that will be exactly what I'll do."