The worst situation like that I ever saw was the last campsite above Deep Creek, in the GSMNP, which is easily accessible from the campground. My daughter and I were pretty tired, having hiked down from Clingman's Dome, stayed at the bottom campsite on Forney Creek and then crossed both Forney Ridge and Noland Divide that day. We'd taken a wrong turn because I was relying on an old topo. Anyway, as we turned into the site, we passed a bunch of locals leaving. One of them shouted out that their fire was about burned down, but "you'uns" can probably get it started back up. Worst mess I've ever seen. They'd been fishing and there were fish skeletons, half-eaten fish and a couple of half-used packages of buns in the smoldering fire. We ended up cleaning it up and packing it out. I briefly considered hiking past them and sending the ranger back to get them, but they weren't carrying anything but fishing gear and probably could have made their escape before the ranger could get there...