There's no way it could tip. The coop itself was barely moved by two large men, then the run was attached, making it quite permanent. I should also clarify that the first layer of pavers is pinned under the coop and couldn't be moved.
Since some of you have posted, I've thought maybe I could strengthen the arrangement by using some mortar and cementing together the paver stones. I'd like to put hardware cloth down, but its gonna be a little hard, since the first set of pavers can no longer be moved (without a ton of effort). I can't imagine a raccoon digging down and under 20" of cement. I've seen people with 1' hardware cloth aprons that they seemed comfortable with. Any thoughts on this idea?