Do you still have payphones? Seriously, about 5 years ago I was out and about (did not carry cell phone at the time), needed to call. . .and no payphones to be found anywhere. They seem to be disappearing. I now am forced to carry a cell phone because there are no payphones where we live. . .

So, maybe find the cheapest pay as you go dumb cell phone and add it to your kit. And a battery powered charger for it. . .just in case.