Daniel Lemire is exactly right in this article, and we forget it at our peril: "Most metadata is unreliable. Maintaining high-quality data is simply hard work. And even when people have good intentions, it takes more mental acuity than you might think." And the system is not set up for it. "One of the problems with metadata in the real world is that you are in an adversarial setting.... you still have to worry that they are going to lie to you."