If I leave something valuable on a plane or in a hotel room, it is my fault, and I assume there's at least a 50% chance someone's going to take it rather than turn it in. That's just the facts of life.

I'll add that I left my iPhone on my seat on a UA flight last week and didn't realize until I was at PHX baggage claim. UA radioed the gate and they found and held my phone, then gave me a gate pass to go retrieve it. I was obviously pretty pleased with UA's response. (Note also that gate passes don't come with pre-check, so I got to see how the other half travels. No thank you!!!)