The Transportation Security Administration has been quietly testing controversial facial recognition technology for passenger screening at 16 major domestic airports — from Washington to Los Angeles — and hopes to expand it across the United States as soon as next year. Kiosks with cameras are doing a job that used to be completed by humans: checking the photos on travelers' IDs to make sure they're not impostors.

The TSA says facial recognition, which has been banned by cities such as San Francisco, helps improve security and possibly also efficiency. But it's also bringing an unproven tech, with civil rights ramifications we still just don't understand, to one of the most stressful parts of travel.