Because SOME PEOPLE have decided to deduct my Geek Points on me just because they've seen me in a dress. =)
Anyway. I'm sure this is documented somewhere, but Adobe Acrobat has a fairly sophistocated "Self-Healing" mechanism to fix certain kinds of corruption in PDF files. I thought that was kinda uber when I haphazardly started messing around with the innards of a PDF file to see what it would do and Acrobat actually approximated the original very closely. =)
And you can tell that it's fixed your file if you open the PDF in Acrobat (not the Reader, but the Acrobat suite), do nothing and close the file right away. If it prompts you to "Save Changes" and you know you didn't make changes, that means it made changes and is now asking you to save.
*thumbs up* =D