I've started using Google's Trusted Contacts
app on my phone. You can push your location to specific family members or friends, and they can request location from you if you aren't sharing all the time. There's a nice safety feature such that if someone requests your location and you don't respond in x minutes, the location is automatically shared with them whether you like it or not. It offers a bit of peace of mind.
I think, for now, just getting a phone with better service is enough. I generally have the phone on vibrate only, and on a ride it goes in a pocket where I won't be aware of a call or a text. I like it that way. I take the phone just in case of something like a bike problem that I can't fix, so I can call Gail (or, I suppose, Uber, though I'd have to figure out how to do that).
As to a feature that tells someone where I am whether I like it or not, that strikes me as pretty much the opposite of peace of mind. :-)
My fear is hitting my head or something, losing consciousness, and not being found before I freeze to death. In that case it would be great if Melissa could direct the rescue helicopter to my last known position before the whole dying part. But I am pretty sure that my brain is more active in the "this is how you could die today" category than most people on AP so I can accept that I may be the only one to use this app. :-)
I have definitely considered using this function as well. I suspect the whereabouts of my partner are much more important when I have a small child at home than they were before (and probably after she is of a certain age... though I don't know what age that will be).
A bit of a close call yesterday. I walked along one of my trails and came back the other way 20 minutes later to find a rotten old birch tree had fallen across the trail in the interim. I suppose if it had fallen on me, an app like Cristina's would have instructed people where to go look for my remains.