Posing as a wealthy, jet-setting diamond mogul, an Israeli conman wooed women online then conned them out of millions of dollars. Now some victims plan for payback.

Everyone knows something like this is happening. But this is the only experiment to fully demonstrate what excessive openness on the internet means. The filmmaking couple hired youthful-looking (but over 18) actresses to pretend to be prepubescent girls and communicate with strangers who approached them based on their fake accounts. They attracted dozens of men in the first ten days, then hundreds, and finally thousands...