In most cases I agree that staying put is the best plan, however there are always contingencies we don't count on. If you have a bug out plan in place it does not mean you have to leave, it only means that you can do so faster and more efficiently than you can with out prior planning. Also any plans or equipment for bugging out can be used when the decision is made to stay. The idea in being prepared isn't to be prepared for a very specific set of events but to be as flexible and as adaptable as we can.