Είχα δει κάτι τέτοιο πιλοτικά στο αεροδρόμιο του Amsterdam, όπου κάποιοι που ταξίδευαν συχνά μπορούσαν αντί να περάσουν κανονικό έλεγχο να περάσουν από ένα scanner που έλεγχε τον αμφιβληστροειδή τους και περνούσαν.

Το παρακάτω link εξηγεί ίσως καλύτερα.
http://www.siliconvalley.com/mld/siliconvalley/8791938.htm

A select group of business travelers and others soon may get to scoot through airport security under a new system akin to having a ``fast pass'' for a toll bridge.

Known as Registered Traveler, the program is due to begin a three-month trial run in late June, using up to 10,000 volunteers.

Details about the program, including which airports will participate, are still being worked out by the federal Transportation Security Administration. But already Registered Traveler is drawing criticism surrounding fairness and privacy issues.


The program's aim is to thin the ranks of the 300,000 passengers a day -- about one-sixth of air travelers -- who now are subjected to secondary checks. By excluding certain frequent fliers from random security checks beyond the standard stroll through a metal detector, government officials say their screeners could better focus on other travelers.