Stripe had a live dashboard over Black Friday that showed the dollar value of all transactions across their network, including those blocked for fraud. The fraud rate was nearly 12% of the total dollar amount of transactions.
Which, we've got to ask about the false positive and the false negative rate. it's annoying when it's really me and I try to charge something and it gets declined, but also the fraud detection can't be 100% effective, so the real rate is probably higher.