[dragonwriter]

> Now, what if she started falsely telling others that BigBank took her money, and that significantly affected BigBank's reputation? Are we talking jail time, or just civil penalties?

Probably not jail time, and perhaps not civil penalties. Even civil defamation in US law generally requires knowing falsehood or reckless disregard for the truth, not just mere falsehood, and criminal defamation, where it exists, tends to have high . Unless the bank had provided concrete evidence so solid that it was unreasonable for her not to believe their denial of responsibility, there likely be no legal wrongdoing.