Not really because nearly every adult has a phone with unlimited calling, and will allow you to make a call from their phone.

This isn't very compatible with also teaching children that they can't trust the majority of adults, and that every stranger is a potential danger.

That trope is pretty dangerous in itself (there WILL be time they have to rely on the unrelated adult), and I'm pretty adamant on teaching my kids that the vast majority of adults can be trusted, instead trying to instill Tricky People in them: https://fitzroyelc.com.au/the-tricky-people-lesson-you-need-...

Good point - folks should stop teaching them that. If your kid is really in a sea of dangerous adults their phone won't save them anyway.