Who are you to say what is okay? She's not your child.
Yes its unlikely something bad would happen. It's also unlikely that you would get into a life threatening car accident. But you still wear a seatbelt. Why? Because it's the precautionary principle, pretty much common sense.
Yes in the past we let children wander, but if you asked those parents in the past if there was some very low cost way to afford additional security like knowing where your 10 year old is, they would obviously take it. But for some reason people take the wrong lessons from the past.
Bad things can and do happen to children, but nearly not as much to warrant tracking them. Even if it were, I'd be reluctant to say that this is okay