Ron Nixon: “With little fanfare, the agency best known for airport screenings has vastly expanded its reach to sporting events, music festivals, rodeos, highway weigh stations and train terminals. Not everyone is happy. T.S.A. and local law enforcement officials say the teams are a critical component of the nation’s counterterrorism efforts, but some members of Congress, auditors at the Department of Homeland Security and civil liberties groups are sounding alarms. The teams are also raising hackles among passengers who call them unnecessary and intrusive…T.S.A. officials respond that the random searches are “special needs” or “administrative searches” that are exempt from probable cause because they further the government’s need to prevent terrorist attacks.”