I would not hand over my mobile phone to a LEO, who stopped me for a traffic infraction. If he arrested me for the violation or infraction and used this device to extract any data I would get a lawyer and try suing the City, County, State for violation of my civil rights. I would also file a complaint with the FBI, accusing the LE agency and the officer involved for the same thing.
Such a device should not be in the hands of traffic officers, as there is no legitimate reason for LEO's at the street level to be equipped with such a device. IMO, a court should have to issue a search warrant to legally use the device to gain such data.