In my opinion it does not make sense that it cannot be "seen" with the fences, a dinosaur inside an enclosure would not have to be conditioned to the fact that visitors can "see" it with a viewpoint, tour or monorail. Visitors cannot see them even though a fence should provide vision. That the fences except the concrete one provide vision to the visitors. It would be interesting if the vegetation affects the vision, the terrain itself and decorative elements such as rocks and others. As much for the fences as the viewpoints, tours or monorail. With aerial and marine reptiles, an exception could be made because viewpoints, tours (aerial reptiles) or monorail (marine and aerial reptiles if the monorail passes near an aviary) are necessary.