I found the following story on Futility Closet here.
"In 1879 Thérèse Humbert was traveling by railway through France when she met an ailing American millionaire named Robert Crawford. She sought medical care for him, and he showed his gratitude with a handsome bequest." This bequest, which she told many people about (though its exact worth was unspoken), was kept locked up in a safe. It was therefore well-known that she had a great deal of money at her disposal.
This bequest gained her a lot of security, and she and her husband were able to borrow money against Crawford's unknown bequest, since she would clearly be able to repay the loans. They lived luxuriously in Paris for two decades off of borrowed money that had been given for unseen collateral.
"When suspicious creditors finally sued her, they discovered that Crawford didn’t exist and the safe contained a handful of worthless papers." She had spread the rumor about herself and no one thought to question it until her debts had gotten out of control. She went to jail for 5 years.
She was not the only woman to do this and succeed (at least for a time). It is amazing how far the word of a 'respectable' woman would stretch; it was apparently good for thousands and thousands of dollars with no need for supporting evidence.
"In 1897 Ohio con artist Cassie Chadwick 'confessed' to a Cleveland lawyer that she was the illegitimate daughter of Andrew Carnegie and stood to inherit $10 million on his death. She parlayed his sympathy into a series of bank loans and lived lavishly until 1904, when she was unable to repay a Massachusetts banker. Carnegie, who denied her story, attended the trial and saw her sentenced to 10 years in prison. She died two years later in the Ohio State Penitentiary."