Are they old enough to drive? Are they really sure they are in a safe territory, with zero chance of being bait-and-switched into a strange or dangerous terrirory? Is the child old enough to handle the volume of traffic throughout the territory? If not, they shouldn't be out there alone.
And bear in mind that it is possible to start in a safe territory, and then get that "You handled that well, let's see if you can do this territory" while being dragged into a more dangerous territory. This is especially true in big cities and in countries where kidnappings are common.