Great thread. My wife and I installed a homemade giant doggie door to make it convenient for our two Great Danes (and us) to let themselves in and out of the back door to use the potty and play. Many of my Great Dane FB acquaintances were concerned about the security of our having a doggie door that was 33"H x 15"W. I told them any burglar who was stupid enough to crawl through a doggie door that big deserves to meet the protective creatures the door was designed for
Not only that, but we also have a mechanical alarm system (my wife's idea) and a few guns we target practice with regularly.