Preacher wrote on Sep 27^th, 2010 at 9:33pm:

DentonDoc wrote on Sep 27th, 2010 at 9:21pm: An unattended pack on a campsite could just as easily be interpreted as "they exited in a hurry and forgot this pack."   I think that's absolutely rediculous and am surprised at the number of people who clearly must forget their own packs frequently enough to think it's a reasonable assumption.  Maybe I'm just that amazing, that I've never forgotten a whole pack on a campsite.   ;D

Preacher, I'm knocking on wood while I type this, but I have never left a pack either.  However, working with kids, I've allowed a pack that I spied on the shore to be "forgotten" as the person responsible for that pack needed to learn a lesson.  We only paddled for 10 minutes before they caught on with my string of inquiries about whether or not we had everything.

As to stuff that was forgotten, misplaced, or otherwise left behind in camp or at a portage trail, here's what I've personally found that were each in plain view and could be construed as reserving a camp site:
1 food pack that reeked (probably mostly garbage); 1 size 4 Duluth Pack filled with gear; 1 medium size day pack filled with rain jackets; 1 tent (not set up); 2 paddles; 2 pfds; waterproof hard plastic case; huge tackle boxes; 2 fishing poles and fishing nets; hardsided cooler; pair of boots; climbing ropes (probably bear ropes); 1 Chaco sandal.

Oh, and I also found a junked aluminum canoe at a camp site once.  In all of the cases that we stayed on the campsite, nobody came back to claim the site, much less the gear/trash.  Like PJ said "Some people's kids."  :-?