Carrying overnight gear on a 6-mile day hike is a bit over the top for me. A 6-mile day hike is NOT a long hike.

I do not think that length is the issue. If she got lost, it was either because the trail was not well-marked, or else she left it. In either case, the hazard cannot be measured by mileage, but by remoteness from other foot traffic. Leaving the trail, not carrying overnight gear, in a lightly travelled area, and jumping off four-foot cliffs, when no one knows where you are, is stacking your mistakes. No one of them seems all that risky, but she didn't notice how she was accumulating risk at each of those steps, until it amounted to a fair bit - enough to land her in a pretty bad pickle.

I am very glad she survived, and her actions once she was in the soup were appropriate and helpful for that survival. It helps even more to not get in the soup and she omitted many prudent steps that could have saved her from that eventuality.