Even with proper planning, there’s so many surprises you can run into on the trail! Like my first time solo backpacking where I got hailed on (see video).
Although google is on it’s way to making trail maps, they don’t really exist yet. They were on the wrong trail and it was getting dark in less than an hour. They were smart enough (I think) to turn around and go back the way they came, but who knows?
They were complaining to each other of thirst and one girl was afraid to be on the trail at dark! All they had were cell phone lights. It’s not the first time I’ve found someone who was turned around just trying their best to follow trail markers and look at google.