I happened to work in designing critical infrastructure for emergency services. We always had a failure in the plan, which is why part of our deliverable was a protocol for paper logging of the calls (ambulance, police, military...) and the subsequent following of the case. It worked amazingly when the system did go down. In part because it was roleplayed, in part because the system went down in a rather convenient time. The data was then added to the digital logs, and all was well in the world, including the people saved by the, and I kid you not, pen, and, paper... and other humans gasp