I don't think the answer is that simple. Sure, cash users are an easy target here, but upon closer inspection things just don't add up. Targeting cash users would have some deeply negative side effects for everyone.

To quote patio11: "The optimal amount of fraud is non-zero". The financial system needs slack, otherwise it destroys itself.

https://www.bitsaboutmoney.com/archive/optimal-amount-of-fra...