My daughter's day care was doing this 18 years ago. She'd come home saying, "Hold the rope, take walk. Hold the rope, take walk." We were personal friends with her day care "teacher". So we asked her about it & it's a safety thing. It allowed them to more easily keep watch on the kids so they could take them for walks outside the fenced in play area. No conspiracies, just the kids' safety while getting some exercise & reducing boredom.