IMO it doesn't really matter if the client sees it, so long as osT does. You can actually make that line whatever you want it to be. But you raise a valid point, and I see that I was correct that it's hidden in .HTML
If the user can't see the text, how do they know they should write Above the line?? Not all email clients are set to add the reply above the quoted text.. (!) and if not, the reply might end up mixed into the reply text.. @[deleted]: It seems the design is not in the web-template, so you would need to 'hack' the files in the system.. don't currently have access to that (but could download it) to see what files neeed to be changed..