Already under the microscope for claims of sexual harassment and questionable labor practices, Uber said it would ban the use of a controversial technology to block regulatory authorities from monitoring its operations. The company's "greyballing" technology is designed to hide the standard city app view in specific cases -- for example, from former riders blocked for being abusive. However, some drivers have used it to circumvent local regulators, a practice that Uber no longer will allow, according to Chief Security Officer Joe Sullivan.