The proofreading side of copy editing is one we don't talk about much. The grammar and content questions keep us entertained.
But we're responsible for making sure the words are spelled correctly. And spell checking programs -- you've heard it umpty-million times -- can't do it all. Case in point:
where / were
This little doozy shows up often. It's not flagged by most spell checkers and it's quite easy to read over it while editing. I should amend that: It's quite easy to read over it while racing through the last few grafs of a lengthy wire story. And that's where it likes to hide, of course.
Lesson? Read carefully and try to read the story more than once.