OS X Mountain Lion: data loss via 'Save As'

How this passed through Apple's Mountain Lion testing is beyond me. "If one edits a document, then chooses Save As, then BOTH the edited original document and the copy are saved, thus not only saving a new copy, but silently saving the original with the same changes, thus overwriting the original." Just goes to show: do not mess with my ability to save my stuff. There is no one-size-fits-all for this kind of delicate stuff.