I don't use C1 but I would put money on what you want not being possible - LR certainly doesn't work that way.
Rearranging keywords is a completely separate process from applying/removing them. Just because a keyword is a child of a parent that doesn't mean it will always (or even most of the time) be applicable to the parent. In fact in far more cases it wont be.
Colours
Red
Green
Blue
Yellow
How often would you move Orange into such a list and actually want it applied to every image that has the parent keyword Colours?
Pretty much every parent/child hierarchy I have is similar.
Maybe some C1 expert will arrive and tell me I am wrong or give a quicker way of doing what you want. If they don't then I would assume the best way to get it done would be to filter by "camera", select all the images and then apply the Objects keyword.