Phonemag notes that in a survey of 85 taxicab companies serving the San Francisco-Oakland and the Washington-Baltimore metropolitan areas, 6,102 phones and PDAs were lost in taxis in the Washington-Baltimore area and 2,754 lost in SF region cabs within the last six months.

The good news is that mobile devices, including BlackBerrys, have a tendency to be returned: some 80 percent return rate in DC and 65 percent in SF.

But just having your device returned may not be enough for a reassuring feeling.

"It is good news that most of the lost devices were eventually returned to their owners. However, simply recovering the lost equipment may not be enough for all organizations," said Marty Leamy, president of Pointsec Mobile Technologies (which commissioned the study). "Corporations and government agencies need to know what happened to their sensitive data while it was out of their hands.

"Without proper safeguards and data encryption," Larny addedit may be impossible to tell whether the information was improperly accessed before the lost equipment was returned."