BilligCharlie

http://www.flyertalk.com/forum/trave...d-tsa-sfo.html

From - http://www.tsa.gov/travelers/airtrav...documents.shtm

"Passengers who do not or cannot present an acceptable ID will have to provide information to the Transportation Security Officer performing Travel Document Checking duties in order to verify their identity. Passengers who are cleared through this process may be subject to additional screening. Passengers whose identity cannot be verified by TSA may not be allowed to enter the screening checkpoint or onto an airplane."

Interesting, I did not know this was possible either, but looked it up when I saw the post.