I just received a call from my wife when she left a suitcase in the tramway. She was busy with our two kids and only remembered the suitcase when the doors had been closed and the tram departed. Since I have the schedule of all public transport on my mobile, it was no problem for me to hunt for the tram taking some short-cuts with my bicycle. However, since I was too late to catch it I just decided to wait a few stations further down until the tram would turn and come back - that I could reason precisely from the schedule. What I did was a 'virtual track&trace' which works excellent in Switzerland since the planned schedules really match the as-is-situation most of the time.
However, the uncertainty we still had was what would happen, if the driver would detect the unattended luggage, take it out and send it to the lost&found office - we would loose a day in retrieval, as it would go there into storage room according to a defined process as my wife found out when asking at that office. Also they do not allow to communicate with the driver as this would disturb his process of driving (just imagine the communication load for all items being lost in Zurich everyday!).
Thus, wouldn't it be great, if you could initiate an ad-hoc real-time track and trace yourself of your belongings ? Or, if you could have a better way of communicating with other people that find your lost items and have the good mind of helping you ?
I'm convinced that this could be really a valuable case for the internet of things for consumers (and all that desperate people would be also happy to pay a reasonable fee for that service, e.g. keymail).
In our case: we had been lucky, the suitcase just came back with tram I reasoned from the schedule and everything was fine.
 C. Frank, P. Bollinger, C. Roduner, and W. Kellerer: “Objects Calling Home: Locating Objects Using Mobile Phones”, in: Proceedings of Pervasive ’07, Toronto, Canada, 2007.
 Guinard, D., Baecker, O., & Michahelles, F. (2008). Supporting a Mobile Lost and Found Community. In Proceedings of the 10th International Conference on Human-Computer Interaction with Mobile Devices and Services (pp. 407-410). New York.