Perhaps groceries wasn't a good example. However in my experience the enforcers of law often abuse their powers. For example terrorism laws are used and abused all the time. What if enforcers decide groceries are actually "one supply". There's a lot of edge-cases including ongoing supplies such as wages, debt repayment, sub-contractors ... etc. Are they "a supply", or a "series of supplies"? Tax evasion is already a crime. People who are already doing something illegal aren't going to care much about breaking another cash ban law. This law isn't about catching tax evaders, it's about taking people's freedom and forcing them to use the banking cartel.