This also highlights the fact that a lot of people on the trails near urban areas do not make a very hardy attempt to self-rescue. They just hit 911 and expect help. They were not hurt. They got off trail, and it was getting dark. In the "old days" we would have just hunkered down until daylight and then found our own way out. Taking a cell phone and expecting a rescue is irresponsible. Every day hiker should have enough gear to survive, if not comfortably, one night out. Weather in Napa CA is not that cold. But I do not know all the details. On the surface, my first reaction is that they should be billed for the rescue.