There is actually nothing weird about this one. It's actually smart & sensible. Growing up, we had a neighbor, in which the side door that goes to the garage, had a window in the door. A thief did exactly what you had said: broke the window in the side door, reached in and unlocked the door from the inside. There was minimal broken glass sound that neighbors might hear, as they were inside the garage. When the police arrived, they said that's one of the most popular & easiest ways for thieves to get in. The problem is, most people don't know about this or even think about it, until AFTER they've been robbed and the police then point out all the way access ways thieves can get into most houses.