I don't know how many times now, I've gone to reply to an rmail, but accidentally hit "Delete".
I have three suggestions to make this a much more difficult mistake to make.
1) Move it to the opposite corner of the dialogue box.
2) Change the color of it to red.
3) Have a pop-up asking if you really want to delete the rmail.
It would probably be a good idea to do the same thing to the report button, I know I've hit that one by accident too.