UberX is apparently illegal in parts of Australia as well, and authorities have been using entrapment to identify drivers and fine them [1]. Having access to a database of drivers would make it easier for authorities to fine the drivers, apparently $1700 per offence.
"NICK MARSDEN, DEPT. OF TRANSPORT AND MAIN ROADS (Aug. 28, 2014, male voiceover): "No covert activity was done today, Uber locked third phone due to penalty infringement notices being issued yesterday. Time was spent purchasing new credit cards, activating Gmail accounts and setting up two more phones. These phones are the last ones, will be ordering additional units.""
[1] http://www.abc.net.au/7.30/content/2015/s4162393.htm
"NICK MARSDEN, DEPT. OF TRANSPORT AND MAIN ROADS (Aug. 28, 2014, male voiceover): "No covert activity was done today, Uber locked third phone due to penalty infringement notices being issued yesterday. Time was spent purchasing new credit cards, activating Gmail accounts and setting up two more phones. These phones are the last ones, will be ordering additional units.""