以前多次入关无事。今日入关遭打指纹照相。上网一查， 2009年起，绿卡入关形同visitor. see the following report:
"Millions of green card holders will be fingerprinted and photographed every time they enter the United States as part of an expansion of a controversial biometric program, the U.S. Department of Homeland Security announced on Thursday.
The expansion of the US-VISIT program to permanent residents--also known as green card holders--takes effect on January 18, 2009. At the moment, the program's biometric requirements apply to foreign citizens with a non-immigrant visa or those traveling as part of the so-called Visa Waiver program. "