But the question is how? The balloon would probably lift off immediately and pull the kid in the sky with him.
So how does one hold down a ballown via a tether then climb in the balloon and have it lift you? Sure you can wrap it around a pole, but then it’s uneven and would be difficult to get into without destroying the flimsy balloon.
If that is what happened I’d be surprised.
Where was it tethered?
And I could see a big brother putting his little brother in the ballon, un-doing the tether and then lying.