RFID is a technology that uses radio waves to read and capture information stored on a tag attached to an object. So you can use it to identify, track and locate objects without contact.
All you need is a device to read the tags, it can be a smartphone, tablet or a borne; a transceiver (device receiving and transmitting data) and a transponder (picking up the information and responding with a wireless signal).
It is very popular in events like festivals because of its convenience and efficiency. It is utilized in many aspects of our daily lives, and the list is growing instantly. You have probably used it already, maybe staying in a hotel that was using RFID cards or wristbands as room-keys or even at some stores self-check-out.