I think it is an author's responsibility to tell the absolute truth when writing a non fiction piece. It is unethical to lead readers in the wrong direction. However, how will anyone ever know when a non fiction piece doesn't have any fiction parts? I think that an author would embellish on an even to make it more interesting, but all they really have to do is add a short sentence such as, this is how it felt, or this is what could have or would have happened.
I have never read Frey's book, but I have definately heard of it. Before hearing about all of the lies that Frey wrote about, his book was very popular. Why couldn't Frey have just labeled his book fiction. I think it is becasue saying that you actually went through something gives it a different effect they saying that you just made something up.