I run, cycle and sometime swim with a RoadID (see http://www.roadid.com/). The type I use is a set of dog tags on a chain that I wear around my neck and while one dog tag carries a motivation message that I was awarded by the Long Island Team in Training Run team (see http://rockstartri.blogspot.com/2009/01/dogtags-pete-buttah-and-joy.html for that story), the other has my contact info and my wife's contact info. I originally got these so that when I was face down in a ditch on the side of the road, the authorities would know who to call to help clean up the mess. Fortunately we haven't had to see if they work for that use-case yet.
Last week during the no-frills 5K, though, I noticed my chain unhitched around my neck and the dog tag with my contact info wasn't there anymore. It must have been somewhere on the course of the 5k but I couldn't find it. The other one was still dangling on the chain so I was able to save it. I came home and after a few days got around to ordering a replacement.
Today, upon our return from vacation, there was a letter with no return address. Inside was a piece of paper with no note but with my dog tag taped to it.
The person who found it could have ignored it and left it where it was. They could have thrown it out, but they didn't. They took the time to put it in an envelope and drop it in the mail. I'm sure at some level it was an inconvenience to this person.
They may have not considered it a big deal and that, in and of itself, is a big deal. Thank you Mr. or Ms. Anonymous for returning my dog tag and more importantly, for restoring my faith in people with this simple selfless act.