Inspectors at Miami International Airport, which has the busiest Federal passenger inspection facility nationwide, inspectors rely on the Advance Passenger Information System. The airlines and cruise companies feed passenger data into a mainframe computer, which is then compared with national criminal records and treasury enforcement databases. The computer system tracks suspects through travel agents and connecting flights, discerns travel patterns and histories, identifies accomplices, establishes nationwide lookouts, and shares intelligence. The system allows inspectors to target suspects for thorough inspection, while allowing customs officers to process other passengers quickly and efficiently. The phenomenon of "swallowers" of cocaine and heroin illustrates the reality of supply and demand in the illegal drug trade. Despite the inherent risk in swallowing pellets of drugs, the money is often too good to turn down. X-ray machines, disposable narcotics test kits, detector dogs, television monitors, and automatic passport readers are all used to help Customs officers detect drug smugglers. Nevertheless, there is still a need for newer, more advanced technology. The smuggling threat extends to sea passengers, courier bags and mail, ocean cargo, internal conspiracies among employees involved in the handling and shipping of cargo, and private vessels and aircraft.