While an undergraduate at the University of Virginia, Joshua Anton created an app to prevent users from drunk dialing, which he called Drunk Mode. He later began harvesting huge amounts of user data from smartphones to resell to advertisers.
Now Mr. Anton’s company, called X-Mode Social Inc., is one of a number of little-known location-tracking companies that are being deployed in the effort to reopen the country. State and local authorities wielding the power to decide when and how to reopen are leaning on these vendors for…