In addition to producing one$-$time unlinkable credentials, blind signatures can also produce anonymous electronic cash. In this case, the issuer I is a bank and the prover P is a customer that wants to get a banknote m stamped by the bank. The bank signs the blinded banknote m$$ without seeing the original banknote m$.$ Then P can recover the signed banknote $($m$,$ s$)$ from $($m$,$ s$),$ and after that spend $($m$,$ s$)$ in a shop, in such a way that the bank and the shop cannot relate the withdrawn $($m$,$ s$)$ with the spent $($m$,$ s$).$ Does the bank become vulnerable to customer cheating due to signing banknotes without seeing them? What kind of cheating? How could the bank defend against such cheating?