Shouldn't information in journalism and nonfiction be verifiable?

Shouldn't information in journalism and nonfiction be verifiable? Let's keep made-up dialogue and internal monologues on the fiction shelf. Here's a blog post discussing that question, for the UK publication of "Empty Mansions: The Mysterious Life of Huguette Clark and the Spending of a Great American Fortune," from Atlantic Books. Read more at http://atlantic-books.co.uk/content/empty-mansions-bill-dedman-and-paul-clark-newell-jr.