Celebrim said:My point is that claiming that intimidate being impossible isn't a railroad by pointing out that the scenario was described in such a way that intimidate was at odds of the goal of the encounter is no defence, because the goal itself is then described in terms which are also a railroad. A well stated goal only explains the primary outcome in the event of success or defeat. It doesn't explain how it is to be accomplished. By definition, if the scenario states that the only way to get from point A to point B is to do this, then its a railroad.
Point of Fact: Getting to point B is likely to happen whether the PCs pass or fail the skill challenge. The challenge resolves whether or not the Duke assists the party in reaching B. Claims of railroading still fall short.