The letters that the district attorneys of Los Angeles and San Francisco sent to the three biggest ride-sharing companies last week allege that the firms misled customers to believe their drivers go through background checks, ensuring they have no criminal record or driving violations, the Los Angeles Times reports. This week, San Francisco prosecutors arraigned an Uber driver who allegedly bashed a passenger in the head with a hammer, heightening discussions about safety, though that driver had no prior criminal record, KTVU reports.