When I first started using email, I didn't realize that replying to an email included the original email that was sent, and I also had the notion that changing the line in the subject matter, somehow made it a different page. I know that I replied to one family member's email and added another family member's name to the send list and there was something in the first email that they had written to me that they would not have wanted the other person to know they were said. By the time I realized exactly how email functioned, it was too late to *unsend* which I could have since the recipient and I were both on AOL. Neither party ever brought it to my attention, so maybe there was a chance that the recipient did not scroll down to see original email.

So the answer is yes, been there, done that.