[rprime]

It depends.

I've worked in the e-commerce industry for more than 10 years, not having proper fraud prevention is something that can bankrupt you. If you _know your customers_, it's easy to create a simple system that would at least notify you of possible fraudulent orders and let you take manual action. Even with the recent Stripe updates, we still see plenty of payments that go through even thought they should've definitely been caught, but because we've our own system in place, they get caught before doing any damage (and subsequently helping Stripe and marking the payments as fraudulent -- I wonder if I can get free Stripe credits for training their models using our own dumb heuristic based code).

[jdietrich]

There's nothing wrong with adding your own checks based on your specific needs, but you need a baseline to build from. An early-stage startup or a small business just doesn't have the expertise to build a comprehensive fraud prevention system. Fraud prevention providers have huge databases to train their models on and an enormous amount of experience and expertise.