Having held a Licence in London for over 20 years, I've lost count of the amount of mobile phones I've returned to owners or handed in at Police Stations over the years.
The only time I've ever left something in a Taxi was in Manila last December, when we left my wifes Christmas presents in a Taxi from SM North Edsa. The driver never returned the items but still believing that all Taxi drivers are decent I returned to the lost property/security office at North Edsa the following day. We told them what happened and asked if the Taxi driver had handed in the bags and were greeted with several of the staff in fits of laughter that we would think a Taxi driver would return the items.
Obviously Taxi drivers in Manila are not regarded as honest as the readers digest survey indicates.