moral obligation?

Over the past few days I have spent quite a bit of time pondering the idea of whether or not a nonfiction writer has a moral obligation to 'tell the truth, the whole truth, and nothing but the truth'. In turn, this has led me to question my own morals, both as a reader and a writer. When I discovered that the scene with the typewriter was purely fiction, my first instinct was to be irritated and perhaps a bit betrayed by the deception. After a few moments of contemplation, I decided that it didn't change how I felt about the story, and was content to leave it at that. After discussing it with the small group, I began to actually think about it in a broader way rather than in just the context of this particular story. Is it wrong to fabricate material when the reader is expecting truth? I'm still not sure. In the context of this story I am more inclined to forgive it due to the personal nature of the piece. Perspective and opinion cause "the truth" to be more of a fuzzy gray area, and I feel that an author is more justified in recounting their perspective even if it is not strictly fact. Someone in the small group brought up the argument that an author loses credibility when you can't trust them to separate fact from fiction. I agree with this, although I am still having a hard time with the question of 'does it matter'? I think that when it comes to journalism and other forms of strict nonfiction, readers both expect and deserve hard facts. When it comes to the genre of creative nonfiction, I think there is a bit more leeway for stretching the truth. As for blatantly inventing whole scenes, I am still unsure how I feel. I do not believe I could do it in my own writing, but I am hesitant to impose what I consider my own personal morals on anyone else. If a writer feels that they are better able to stay true to the story by deviating from the facts, is it really such a bad thing? The best conclusion I can come up with is that it depends on the situation, the subject matter, even the intended audience, but ultimately is up to the author to decide for themselves.