The game is full of these fences that block player access to certain areas but allow infected in, and I am always at a loss to explain why the government would erect such systems. What's the utility of that?
Although, perhaps this is just another variation on the theme of heroes that can't overcome mundane obstacles like chain-link fences and chest-high walls.
Shamus Young is a programmer and writer by trade, videogame nitpicker by inclination. If you have the patience for more of his ramblings, they can be found at ShamusYoung.com.