Forget about "that's the downside." That answer wasn't from a teacher.
In the good old days, kids would roam the neighborhood freely and parents didn't have a care in the world. Nowadays, parents worry about all the possible, but statistically unlikely, things that could happen to an unattended child (like kidnapping) so they tend to over-parent and never let the children have a moment without being supervised.
This attempts to give the parent some peace of mind (by being able to find a kid who is missing) while still allowing the kid to experience some freedom.