It sounds like a corollary to Douglas Adam’s Somebody Else’s Problem field or Murphy’s Law… J. Bradford DeLong suggests a natural law of proofreading that deserves wider consideration.

My father believes that one should leave typos in one’s galleys uncorrected. It is a law of nature that when one opens the printed version the first thing one will see will be a mistake. If you leave the typos alone, the first thing one will see will be a typo. If you correct the typos, the first thing one will see will be a truly horrible and inexcusable substantive error: