Yeah but if it's their mistake, which can happen (click link at the bottom of my post for a £10 note that should never have made it into circulation), then why should they take it back, it doesn't neccessarilly mean it was stolen, just that it got put into the wrong pile at the Federal Bureau and distributed out in error.
http://cgi.ebay.co.uk/MISPRINTED-1993-BANK...VQQcmdZViewItem