Interesting observation: You prevented a "uh oh" from turning into an "we're dying" state. It sounds like your friends are pretty hardened for the backcountry, and they needed to get out, but it wasn't life-threatening (at the time). Something we should consider while designing these systems. I think the pricepoint of InReach services certainly prevent casual usage (sending memes, browsing instagram) but allows sufficient communication at a reasonable price to coordinate safely.

Also, with 5ft of snow coming down, I have my doubts an iPhone would be able to reach out and touch a satellite. It'll be interesting to see some tests.