I didn't see this asked, but I just skiimed the comments. The part about points being used by owners or owners families.. How do they know who is my family or not? What constitutes the owners family? Does that just mean me and my immediate family? My in-laws? Cousins? How would they know if John Doe is my brother in law or not? How would they enforce that short of saying that someone whose name is on the contract must be registered as a guest on every reservation? My hypothetical daughter could get married and no longer share our last name. Would that mean I could not make a reservation for her and her husband? Would they require documentation upon check in to prove she is family? I just don't see how they could possibly enforce private rentals. Sure they could crack down on the rental companies, but I'd think it would be hard otherwise.
So fraud software is AMAZING. It knows that my friend, who I've known for 35 years, is my friend. Its easy to map to public records - marriages, births, divorces. But fraud software does SO much more. It knows when we've been to restaurants together. It knows we graduated from high school together. That we worked together. That we've been on a plane together more than once. It, of course, knows we are Facebook friends, and have been for a LONG time. This is how your credit card company knows to contact you when the big screen TV that was purchased on your account is sent to a stranger - and why it doesn't contact you when its sent to your brother.
So your hypothetical daughter is linked to you by her birth certificate and to her new last name by her marriage certificate and name change - that's the EASY part. Your best friend from high school can check in on a reservation you made because you have a long association in records.
ETA: It, of course, isn't 100% - which is why sometimes your credit card company calls you went you sent a big ticket item to a friend. But DVC can make those calls as well - or they can just flag it - one or two people who fraud software can't connect you to, that's OK. Ten in a year who fraud software can't connect you to - that's a pattern of activity worth flagging.