Ultimately I don't think it is right to fence off a large area of an estate when the public have a legal right of access. But I would like to see this project succeed and foster a growing desire in the public to have some large mammals reintroduced, principally because of the positive aspect of their ecological impact.
The really grown-up approach would be for ramblers to be able to access the full reserve (not the 500-acre site) along with the animals, as this would potentially do more to demonstrate the negligible risk to humans than any PR campaign. It would serve as a model for the eventual reintroduction of these species to the countryside. In a strange way, maybe this is why this is happening, if the rambler issue is solved it may really start to give this movement some headway.
I think it is dangerous to see 'rewilding' as something that must be done by keeping humans out, by fences or even gunpoint, as has happened in some parts of the globe. There is the potential here to change the scottish countryside in such an amazing way, and I don't believe electric fences separating people from animals will achieve that.
However, in light of what I just said, I think the one species Paul Lister should not attempt to bring to this project is the brown bear.