Why it's OK (but not recommended) to lose your purse in Japan

So, sometimes I'm forgetful and lose track of where I put things, but it's been a long time since I've lost my purse. That's something I used to do when I was around 10 (and maybe 15), but not since I've turned 20. At least, not until last Sunday. (Oh wait, I did lose my wallet once a few years ago, but that was because it fell out of the door of the van. And that's another story--but I did get it back.)
Anyway...last Sunday evening I went out to dinner with a couple of friends, and I was riding the train back home with Jenn (a fearless adventurer). We were having a great conversation. Our conversation continued as we walked the two blocks from the station to my apartment, and kept going as we mounted two of the four flights of stairs. But then, I realized it: my keys were in my purse, and my purse was...NOT in my hand. It HAD to be back at the train station...or on the train. I froze, not knowing what to do, but Jenn was practical and said, "Let's go get it."
We turned around to walk back to the station through the rain, realizing that we would need to get a Japanese speaker on the phone to be able to explain the situation to the train attendant. Thankfully, our friend Haruna was available, and she heard the whole story and then was ready to translate for us when we arrived at the station. We found an attendant and offered him the phone, to talk to Haruna. She explained the situation and then...he asked that we come with him to the next station. We were hoping he could call someone to find out if the purse had been left on the train, but there was a little bit of a hitch.
The train we'd been riding was the Linimo, which proudly proclaims itself to be "a fully automated train." Translation: no conductor on the train, station attendants only at select stations, and a free opportunity for any passenger on the train to pick up my purse and walk away with it. There was no way of knowing if my purse was on the train (or if it would come back with the train) until the "fully automated train" went to the end of its line and then returned to our station. Having nothing else to do, we waited, and prayed. Then, we celebrated the honesty of the people of Japan, and of God's protection over little things - my purse arrived back with the train. My cell phone, camera and wallet (complete with ID cards) were untouched. I was, uh, pretty thankful. :)