Once I was in a seat close to the front of Y on CO (due to elite status) but traded with someone in back to sit by a friend on the same flight. I left my Blackberry in the seat. But then I realized it and went back to get it. The PAX who I had traded with (giving him a better seat) had it and gave it to me immediately when I asked. But it was pretty clear to me that if I hadn't asked for it, I never would have seen it again.

In contrast, once on a fast train from Tokyo to Kyoto my daughter left her digital camera (an expensive one). When we checked into the hotel we asked the staff to help us. They located the camera in Hiroshima and had it sent express mail to our next stop on our trip with no cost to us!