I attended a talk by Coinbase. They get A LOT of fraudulent activity (both high end and amateur). They have like 7-8 employees who handle all the manual aspects

I attended a talk by Coinbase. They get A LOT of fraudulent activity (both high end and amateur). They have like 7-8 employees who handle all the manual aspects of user verification. So they have to rely heavily on automated solutions. I have never used them so I don't know how often they flag false positives but based on that talk I would at least qualify the statement with "it's a hard problem!"