Smart phones are unlikely to be returned by those who find them, but very likely to be perused for sensitive data including photos, social media applications and banking applications. Only half of those who found the phones made any attempt to contact the phones legitimate owners. The Smartphone Honey Stick Project seeded public spaces in various cities with 50 smart phones loaded with tempting, albeit fake, personal and corporate data. The phones were equipped with spyware devices so that they could be easily monitored. New Yorkers were the least likely to return lost phones.
Source: https://threatpost.com/symantec-experiment-half-those-who-find-smartphones-dont-return-them-040412/76404/