If anybody is wondering why all of us are legally subject to searches at airports (NYC subways, schools and other exempted places), just read New Jersey vs T.L.O. (1985). The Supreme Court ruled that there are some exceptions to the 4th Amendment... "exceptional circumstances ... beyond the need for normal law enforcement [that] make the warrant and probable cause requirement impractical." Feel free to turn down that CBP or TSA agent. You might not be arrested but you'll be required to leave the airport and might have to answer to your employer why you were unable to fly that flight.