You think the US is being a stickler by requiring a passport or special driver's license to cross the border?  The EU is planning on making visitors from other countries submit biometric data, such as fingerprints and other data, to enter their borders.  (http://www.iht.com/articles/2008/02/10/europe/union.php)  One can only guess at what the other data could be.  Retina scans?  Urine samples?  Blood samples?  What is this, Gattaca?  (http://www.imdb.com/title/tt0119177/combined)