Oh wait, sorry!  they are protecting us from terrorist musicians!  er, wait... musicians who have names similar to terrorists!  

U.S. Homeland Security Bars Famed Mexican Acoustic Group, Forcing Group to Cancel Sold Out U.S. Tour Dates

Government Says Rodrigo Sanchez Has Name Similar to Barred Foreigner

MEXICO CITY-A renowned Mexican guitarist, member of the ATO Recording artists Rodrigo Y Gabriela, has been hold (sic) up here for over two weeks since the United States Embassy declined to renew his P-1 Entertainer Visa. This unexpected situation has led to the cancellation of half a dozen U.S. shows on Rodrigo Y Gabriela's current tour, and put in jeopardy many other major concerts and promotional appearances.