With a perpetual ZOO at my house we're considering adding a Doggie door to the back door that lets out into the backyard. It's a completely fenced-in backyard with locked gates and a 5-foot privacy fence, so we aren't particularly concerned with a person necessarily being able to, first of all, get over the fence, and second of all, being able to crawl thru the door when we aren't there. (I'm sure there are cases where this has occurred but with the house being at the end of a subdivision and facing a main highly traveled street, we aren't that concerned. Plus we have cameras).
With a perpetual ZOO at my house we're considering adding a Doggie door to the back door that lets out into the backyard. It's a completely fenced-in backyard with locked gates and a 5-foot privacy fence, so we aren't particularly concerned with a person necessarily being able to, first of all, get over the fence, and second of all, being able to crawl thru the door when we aren't there. (I'm sure there are cases where this has occurred but with the house being at the end of a subdivision and facing a main highly traveled street, we aren't that concerned. Plus we have cameras).