I have been preaching for years to have people put their contact information on all of their fly boxes. There is enough down time in winter that a person should be able to use a few minutes of it to label your boxes. Most don't. Like Tim, I have found flies and gear along the river or at a lake that took a long time to acquire/tie and were lost forever for lack of taking the time it takes to tie one fly to insure it's return.
We need a day-probably in January-called "Label Your Fly Box Day" -where we remind each other of the importance of doing this and dedicate some time to getting it done. Maybe call it Fly Box Friday or something. Anything to break up the winter doldrums and perhaps head off some grief later.