The Parliamentary press gallery regarded the publishing of the emails as the scoop of the year.
Presumably, if the emails between Peter Dunne and the journalist were stolen then it would be okay.
The emails and the phone log weren't stolen. Parliamentary Services, who held them, handed them over to David Henry. He was undertaking an inquiry the Prime Minister ordered into the unauthorised disclosure of a sensitive government document. Henry is a former Commissioner of Inland Revenue and hence is well-used to overseeing the handling of sensitive material on politicians, journalists and everyone else.
The emails weren't published and weren't used in the inquiry. Peter Dunne and the journalist emailed each other prolifically, up to 23 times a day. Their emails would make far juicier reading than Don Brash's musings on policy and political strategy. I fear the world has lost out on an exciting book, a play, and, quite possibly, a steamy movie.
The other reason I have no sympathy for the case is the journalist's amateurishness. Dunne's emails and phone log are all run by the Parliamentary Service. That creates an obvious and easily managed risk.
When I was an MP I dealt with a great many whistleblowers. I never communicated with them through a Parliamentary phone or on a Parliamentary email account. I felt the risk to them was too great. There were several government and police inquiries into my sources. They were never caught from my end. It's journalism 101 to be using a phone and computer under your full control for the purpose of all sensitive communications.
It's a mark of the professionalism of the Parliamentary Service that the journalist's emails have not been leaked. It's a shame: they would make a great movie.