On MSNBC they showed this thing pretty close-up. It looked as if the whole thing was covered with the mylar, and that there was no “door” or any other place that the kid could have gotten in.
Obviously, the dad that constructed this knew that, and one would assume that he told the authorities that there was no way that the kid was riding in what was left in the sky being photographed. The only way the kid would be riding would be in another attached “box” that they are talking about falling off.
I’m not sure why they even bothered tracking the balloon, as they would have had to know from the parents that there was no passenger compartment remaining.
When it landed, there didn’t seem to be much urgency on the part of the people on the ground. If they thought there was a child in there, they would have been hustling to get him out.
I think they knew the outer compartment was lost and were just following it to be sure.