Because nobody (oh, the arrogance of the boy :-) knows what the opposite of a "backup" actually is? Besides, what kind of "opposite" do you mean? Obverse, reverse, inverse, converse? Second verse the same as the first? (PS your mail server won't let my mail through, doesn't like gmail :-P )

interesting thought When asked what the opposite of inside out is, most people will say outside in. In fact, the opposite is inside in OR outside out.