As someone who's very forgetful and tends to leave things behind, I must disagree. When I was in college a few years ago, I left my door unlocked for a period

As someone who's very forgetful and tends to leave things behind, I must disagree. When I was in college a few years ago, I left my door unlocked for a period of months, because I had lost my keys, but replacing keys required a fee (increasing every time) and was generally a cumbersome process. I suppose an easy solution would be to not have an obnoxious fee, but if I had had a Lockitron, I could have just used my phone, and if I lost my phone (which, of course, has a remote GPS function), I could have switched to a new one. A different use case: over New Year's I was on a trip to Germany, working with some friends in a hackerspace there. Since it was a private space (and open at all hours), the door was not kept unlocked, but a relatively large number of people had access to it. The hackerspace could have handed out keys, or used some more complicated keycard system, but instead they used a Lockitron-like device (not sure which one; it being a hackerspace, they were managing the lock over SSH!). This way they could give anyone (potentially temporary) access without complicated logistics. First world solutions.