Membership of the United Nations should be conditional on "foreign" journalists (TV, radio and print media) having quasi-diplomatic status with the same journalistic freedoms that they enjoy in the country where they are accredited. That would make it pretty difficult for Governments to abuse their people in secret.
It may seem a bit unreasonable to faciliate all of the activities of tabloid journalists and paparazzi but the problem with trying to come up with a set of "United Nations" rules for journalism is that the liberal governments might be just as interested in applying restrictions which they would happily "blame" on the UN - "We'd love to be more open, but we are not allowed".
The recent revelations about Andrew Marr shows that even journalists are not above a bit of secrecy when they can get away with it.