I found a cell phone on the Tanner Trail in the Grand Canyon backcountry. The Tanner is normally considered a trail that only very experienced hikers should take. It had a "home" entry and I called them later. Cell phones do not work in that part of the Canyon. I described the location and it turned out that their 13 yo son got some snacks out of his backpack at a rest break and dropped it. They sent me a nice thank you letter but did not offer to pay the $10 FedEx cost.

I left some valuables (about $500 of misc electronics) on a DEN-PHX flight and went to the UA lost and found the next morning and it was there. Karma....