Well, would you notice somebody sitting in a car 100ft away, taking a picture at the moment you put your key into the lock? A picture of a key on a table is useless anyway, since you (most likely) don't know what lock it fits with. With a van with a computer and a small key-making tool in the back, you can sit somewhere until the residents come home, take a picture and have the key made by the time the residents go out again and then you can enter without breaking anything.

Of course the camera can be hidden so that nobody would even see a guy in a van taking pictures, just a guy eating a sandwich who could push a button to take the picture unnoticed.