You can find a place with zero fraud by denying all transactions. This is of course, maximally inefficient and totally useless. It's less about "allowing frau

You can find a place with zero fraud by denying all transactions. This is of course, maximally inefficient and totally useless. It's less about "allowing fraud" and more about managing false positives in the fraud detection subsystem: it should ideally detect fraud, and only fraud. The false positives need to be low enough for the system to work, without also having so much fraud that the system stops working. Ideally there are no false positives at all, but at some point the effort to reduce this further exceeds the returns. Like with fraud.