Privacy experts say the pilot program is too vague to guarantee anonymity. The program will track riders who are using the Massachusetts Bay Transportation Authority (MBTA) system in 10 of its stations in Boston and Cambridge. The company says riders will be tracked only if they, download an app that utilizes the technology and opt in, to allow the app to receive the beacons signal. Privacy expert Bruce Schneier, CTO of Resilient Systems, said this program probably ranks on the low end of the risk to privacy, although it depends on the details”]