Expect the unexpected
I'm not going to mention names, I don' t want them to come and get me. I worked for a large utility that had gone to the effort of having two centres, six miles apart, away from known aircraft routes, fault lines, rivers, volcanos, lay lines and crop circles. They then built their billing machines over in the sites, 100% redundancy of everything, right down to power from different grid supply points (we're talking 400,000V network tracing). As a utility, they billed millions a day at sod all margin, so they needed the cash flow to pay suppliers quickly, we used to talk about 10 days without billing means even the banks would stop lending money.
I was a grad given a project to check the business continuity, what was expected to be another pointless exercise they ran every year to keep the useless grads busy for a month. They were in for a shock, a factory that was halfway between our sites and used to process nothing in particular had changed hands, so I wrote to them asking what they did for business contiuity and if we could learn anything, seemed like something to do in my month to write this report.
The start of paragraph two said it all "As a processor of chemicals who have a statutory 10 mile exclusion zone should there be a confirmed leak......"