I don't lock my doors either because I have a very large dog (Great Dane) who is my shadow. I have had alot of contractors in and out of the house over the past few months and I think I'm gonna have to start locking up. I decided this when I watched one of my Amish contractors climb in the window hole (replacing the window) and my Great Dane watched him do it. OP, I would have been terrified. I'm with some of the crew above and think that this guy knew where he was but was making it up on the fly.