Regardless, parent’s point is that there’s no wall keeping them in.

As an aside, the Spartans famously claimed that they were their wall. But I wonder: Spartan construction was very simple, and they despised those with expertise or a craft (the small class of free noncitizens who along with the helots did all productive work). Maybe the truth is that a project with the scope & complexity of a good city wall was simply beyond them. They couldn’t do it, so they told themselves a sour grapes story about how they never wanted a wall to begin with. Just a hunch but I like it.