How much newfie can a rabbit hutch, fence and window take.

I'm begining to wonder, I also feel sorry for the rabbit whose hutch the newfie has already tried to open before, I'm wondering how long until the poor thing has a heart attack.

I was around someone's house yesterday when as I was walking up to the front door I saw the neighbours Newfie trying to get out of the window, which although open but closed so it couldn't move but would allow a bit of air in was shaking under the strain, but that was nothing new, then I went into their back garden, when I heard a noise and saw the Newfies head hanging over the siz foot fence, now although newfies are big I also know that there is a rabbit hutch their that the dog must of been standing on, the poor rabbit, I'm also wondering how much longer a rabbit hutch can put up with having such a heavy load on it, and how long the fence can either, as although the dog is friendly, I'm wondering if the persons kids are in the garden how many could get accidently hurt if the fence fell through and wood or even dog fell on them, or if the dog got into the garden and knocked them onto the pavement, I think that owner does try to stop the dog, but the dog doesn't get out nearly enough so has pent up energy and anything new is great, which doesn't help anything at all, I've offered to take him out, or for them to come on walks with me and my dogs, but as of yet nothing has happened, and I know that their planning on getting another newfie soon...

I'm not quite sure why a newfie looking over a fence equals child getting hurt.
My dogs play rough and jump about, they also all like to stand on my rabbits hutch. My rabbit is still well and my son is uninjured