Over at Gristmill, there is a good article about planning in the face of possible accidents. Specifically, it discusses the massive coal ash spill in Tennessee. The article stresses how responsible planning must make a genuine attempt to estimate the probability of a catastrophic accident taking place, as well as the likely consequences of such an accident. Excluding worst-case scenarios from planning makes it likely that plans will go forward which are unacceptably dangerous. It also makes it more likely that possible defences against a serious accident will not be established.
Many of these points are similar to ones made about financial risk by Nicholas Taleb. In both cases, there are very serious risks associated with making plans on the basis of ‘ordinary’ outcomes, while ignoring the possibility that things will become far worse than you anticipated.