But this is a prime example of marketing - or an A/B test gone wrong.
It reminds me of my favorite quote: "If you run enough A/B tests online, you'll end up with a porn site"
If you have a customer support team and get them to obsess over reducing the fraud rate - you may achieve this goal, but you end up treating every customer like a potential fraudster. (H/T Rabois)
So you pair this metric with a counterbalance - e.g. customer satisfaction