While in Rome the first time, I carried a good size Domke bag with some travel documents, my FE2, my Leica with three lenses, some traveler's checks, + film-- some exposed.
At dinner, the waiter evidently pushed it under the table which had a table cloth to the floor, and I left without it.
About midnight I started looking for it, -- it took me until the next afternoon to eliminate all the places I could have left it, and I called the restaurant. They had the bag hanging on a hook in the coat room. I gave the guy $20 for taking care of it, (it was 20 years ago, he was quite happy, and a cheap price for my lapse in memory), got a taxi to do a tour of Rome in 30 minutes (for Rome taxi drivers, traffic lights are decoration), and returned to the hotel.
When I am on a travel day, I try to limit the bags, and remember the number of them with me at any given time so I can limit my memory and physical losses. Much easier when traveling with friends.
Around the house I have things I have looked for now and again for 20 years ;-) I know there is a rare print somewhere in the attic made by my Uncle Semo of Irina Baranova in the 1940's, , and now, those negatives of a couple of my better shots?
I have enough camera bags, many acquired in various trades or actually quite nice freebies from the junk bin at my long time camera shop, -- to keep certain kit together, such as my M8 and the preferred lenses of the moment, my Contax G series bodies and lenses, wedding kits, or the Xpan. It gives me a bigger target to look for, and confusion to any burglars ;-)
I used to put my name on Dymo tape inside of the battery compartment of some equipment, and got a light meter and calculator back that way. A sharpie to write your email on a battery today might enable someone to return lost equipment, perhaps a dymo label inside the bottom cover of a Leica? Perhaps the first shot on every memory card should be of you holding a sign pleading for the camera's return, or I suppose an identity file in its own folder.
I used Kodachrome, posted to Kodak labs at one time all over the world to be home when I got there, but put printed stickers with my address on each cartridge before I posted them. ;-)
My friend found an M3 on the bench at an airport, left his name with lost and found, -- no one called, so he could keep it with a clear conscience.
Another category is the lens you put down after changing to another while shooting something of interest.
Finally, I never looked for any of the idiots who engraved their SS# or names in the top covers of any Leica equipment I may have acquired.
Regards, John