I live on the outskirts between Yellowstone and Grand Teton national parks. While myself and locals access the (truly wild) back country regularly (it's generally why we live here), it's also really important that the 4+ million tourists from urban and suburban environments have visitor centers, boardwalks, signs, rangers, and guides. That middle ground is necessary for their safety as well as area around it. Yes, they will mess it up (or themselves) if allowed to roam freely - there's just too big of a gap between what they know and the real world. It would be great if that gap were less, but it's not, so I don't see a way around it. I'm just happy that so many have the desire and the opportunity to at least get that close.