That might be what they tell investors but I disagree that they've gotten good at policing accounts. I moderate a large Facebook group and we get flooded with join requests from obviously fake users all the time. Most of them have a handful of southeast Asia friends, some random highly geographically distributed friends in the English speaking world, and stock or stolen photos. The real giveaway is the programmatic nonsense responses they give to the membership questions. I've been reporting these accounts to Facebook a long time and they persist, often with join dates making them multiple years old.