Craigslist - what to do when bad people get onto Social Networks

This story on TechCrunch about a Craigslist classifieds cheat event is indicative of the "Dark Side" of Social Networking (assuming that it is reported correctly, of course - it has a sense of the absurd about it):

Someone placed an ad on Craigslist saying that anything at a home in Jacksonville, Oregon was up for grabs. People responded, and carted away most of the belongings of resident Robert Salisbury. He arrived home to thirty people picking over the last of his stuff. Even the man’s horse was taken.

And this isn't the first time its happened, either. Also, clearly the people ransacking his home weren't exactly pure either - on remonstarting with one looter:

"I informed them I was the owner, but they refused to give the stuff back," Salisbury said. "They showed me the Craigslist printout and told me they had the right to do what they did."

The driver sped away after rebuking Salisbury. On his way home he spotted other cars filled with his belongings.

Once home he was greeted by close to 30 people rummaging through his barn and front porch.

The trespassers, armed with printouts of the ad, tried to brush him off. "They honestly thought that because it appeared on the Internet it was true," Salisbury said. "It boggles the mind."

Hmmm...if I was of honest intent and true, and the owner returned in such a situation, I'd be inclined to believe him and desist, non?

So what now? Craigslist advertisers are anonymous right now, so finding the scammers will be very difficult. And as the comments on TC note, once it is clear this sort of behaviour can go unpunished, it can only proliferate and possibly worse things can happen. The game theory implies this quite clearly, as there is no recourse for the victim via the perpetrator (who we can assume to be nearly untraceable in future), nor via Craigslist, nor those who (probably) knew it was a scam but benefited from it - so no-one is motivated to fix it.

(Addendum - Some believe that Craiglist is just a pass-through service so will have no liability, but as TC notes, its not clear and some lawyers are bound to have a go. Craiglist's risk is if (i) something far worse in scale than this happens and (ii) they get nailed for it, as I suspect no one will insure them, as they have taken no precautions to prevent it.)

Realistically, the only answer is for Craigslist to insist on authentication by advertisers of goods, as that is the only way that the perpetrators will know they have a chance of being found. Or is that too Olde Media a plan.....