That doesn't obviate the need to communicate with others (whose concern is rational or not). The communication systems after things like this are down because of (according to you and others here) irrational people concerned about those they love and care about. A system like this has applications to any sort of disaster, and one of the primary benefits is in reversing the order of communication. Instead of 10s of people contacting each resident and swamping both the person and the network, the resident can push information out to the global network. They communicate one time (ok, practically this isn't sufficient to communicate their status to everyone and some will still call them or reach out via other channels), and everyone that cares can check on their status.