I read an interesting essay last night by an american poet called Ted Kooser who was basically saying that he felt writers should not write what seems like autobiographical poetry unless what they are writing is absolutely true. His view is that a reader implicitly trusts that what he/she is reading and responds accordingly (i.e. feels sypathy for the writer etc). If the reader believes that a poem is a true representation of the poets life and then finds out it is fictitious they feel cheated.
I found this very interesting. Personally I always view poems as being fictitious (like novels) unless the writer states otherwise. I often use things from real life as a starting off point for poems - but my poems are sometimes written by a fictitional narrator, I use real experinces but change them or add to the in the same way that I might do if I was writing a novel or a short story. Obviously if I was trying to write my autobiography I would do my utmost to try and recreate a true account of the events of my life. Poetry, however, I use to explore life events - events that really happened and the ones that didn't. Writing for me is a way to explore alternate realities. To do things differently, to imagine what might have happened if things had been different. I do not do this to try and deceive the reader. I see writing poetry as similar to writing short stories - I create a little universe that I hope the reader can believe in for the time that they are reading it. That is what I look for in the poetry I enjoy reading too.