Indeed, such a system wouldn't be out of place in the world of Minority Report, where iris scanners are everywhere and used not just for security, but to identify individuals in public places and deliver advertisements or messages tailored specifically for them.
To get one of the Nexus ID cards and zip through airports and other border crossings, all you have to do is fill out a detailed application at a designated airport and submit to an interview, iris scan and fingerprinting.