Considering the tender age of Jo, both the endings seem a little irrational. It is certain that she will be learning from whatever she hears and visualizes at this age. If the story ends according to Jack, Jo will never be able to question anything she considers wrong in life since this ending stresses that elders are always right in whatever they do. In addition, the story shows the skunk’s mommy hitting the wizard for no fault of his. The wizard had only done what he was asked to. This may scare the four-year-old Jo, as it teaches that mothers, being elders, have the right to hit anyone, even if they are not at fault.
On the contrary, if the story ends as Jo wanted it to, it will stop her from believing in and respecting her elders. She may even start believing that there is nothing wrong in hitting elders.
A balanced view may be given in an apt ending, where the mommy either does not hit the wizard at all or realizes her mistake soon.