Amusement parks put RFID wrist bands on children so they can be quickly located if they get separated from their parents. The technology might even ameliorate the age-old problem of lost luggage, which is maddening for passengers and costly for airlines. An RFID baggage-tagging system in use at the Las Vegas McCarran International Airport reduced lost luggage by about 20 percent, and bags that do go astray are located more quickly.