To be fair, you can do it and go see all you want. Just don't change any of the settings, especially the Sandbox ID. Doing that will put your console into a bad state that you may not be able to recover from.
But that's where you can access Major Nelson's secret diary and read all of his hopes, fears and dreams. Scandalous content, all of it. I had no idea anyone could feel that strongly about goldfish crackers.