U.S. Customs and Border Protection has rolled out facial biometric technology to spot suspicious travelers at points of entry. The tools reduce immigration lines, but at what cost? Machine learning tools predicting human behavior have been found to be racially biased, and privacy advocates worry about government collection and storage of traveler data. Then there’s the risk that actual threats could game the system. But polls show Americans are just as worried about terrorism as they were after 9/11, so privacy and fairness may not survive the screening process.