On the desk or open in a drawer, it is protected. But just sitting on the desk for anyone to see, it isn’t for anyone lawfully in the room—so a burglar wouldn’t have any rights because of the crime committed in entering the room. Someone hacking your emails is committing the crime of accessing your emails and therefore the emails are protected. Looking over someone’s shoulder is not protected. It is his responsibility to make sure the area is secure before opening or writing the email.