I have always figured that I only need to mention if I add something to a quote: otherwise, what I put in my text was in the quote. So, with actual words, if I added them, I put them in square brackets: otherwise, you can assume I found them there. Can't we do the same thing with italics? If I don't mention I added them, there they were. Why do we need to specify both "Emphasis added" and "Emphasis in original"?