Perhaps I'm knocking on open doors? I searched the forums but couldn't find any discussions about this. If you're more lucky, please give me an URL.
I don't know if this is to be considered a bug, but anyone can read your drafts simply by entering the post number to the url by hand.
I use drafts a lot, both as an online persistent clippboard, and for stuff that's just not finished yet.
I don't want people reading any of it, naturally. If the reader pays a little attention he/she might notice there is a gap between to post numbers, and try and access the number in between...