Maybe you could add the predictable human irrationalities as an input signal. For example decision paralysis - I'd expect legit customers to take a bit longer f

Maybe you could add the predictable human irrationalities as an input signal. For example decision paralysis - I'd expect legit customers to take a bit longer for pages that require a decision. Or the way people react to discounts - a fraudster wouldn't care, but a legit customer would be happier and thus less a little bit less focused.