Confidentiality Hinders Error Discovery

While reading this article from 2008 on the Hitler Diaries affair, the following paragraph caught my eye:

Trevor-Roper's main mistake, he told Knightley, had been to sign the confidentiality agreement that Stern had thrust at him in the bank vault in Zurich. By signing, he had deprived himself of the facility that every academic cherishes - the freedom to consult his colleagues.

Hugh Trevor-Roper was the historian whose reputation was destroyed when he was taken in by the forged diaries.  Philip Knightley was a journalist for the Sunday Times, the newspaper that published extracts from the diaries on its front page.