Sometimes we, digital preservation people, have a tough job to explain the surprises we come across. If similar situations would happen in the analogue or physical world, one might doubt our observation qualities. Who could imagine that a poem in a book that is on a shelf in a safe and monitored area, and is opened after a few years, suddenly has some new sentences in it, while no human being did add these sentences? Or that the title page has changed and that the special font, designed and chosen by a famous typographer, turned into a run-of-the-mill font, thus downgrading its aesthetic appearance? Again, without human interference. Panic would be huge if this would happen in our libraries and archives.
Source:Digital Preservation Seeds