Unfortunately, incompletely wiped smartphones routinely show up on ebay, Amazon and other national sellers which have hundreds of thousands of active listings daily. Robert Siciliano, a personal security and identity theft expert, purchased 20 different devices from Craigslist users in early 2012 and found that three of the devices had never been wiped.
http://mobileenterprise.edgl.com/news/Data-in-the-Dumpster-84579