The reason why they let their kid do it is simple. Everyone thinks fish are cut and dry easy.
If the whole bottle fell in, that little girl probably said "Oops" and left it in, thinking that they'd just eat it sooner or later, Or, didn't care.
That's like my future sister in law has a big angelfish in a tank about half the size of my quarentine 10!! I'm amazed that the fish actually lived long enough to get that big....and I'm tempted to buy them a bigger tank, gravel, bubbler and decor for their fish for Christmas!!