Wikipedia
In security, piggybacking, similar to tailgating, refers to when a person tags along with another person who is authorized to gain entry into a restricted area, or pass a certain checkpoint It can be either electronic or physical The act may be legal or illegal, authorized or unauthorized, depending on the circumstances However, the term more often has the connotation of being an illegal or unauthorized actTo describe the act of an unauthorized person who follows someone to a restricted area without the consent of the authorized person, the term tailgating is also used "Tailgating" implies no consent (similar to a car tailgating another vehicle on a road), while "piggybacking" usually implies consent of the authorized person
Piggybacking_(security) - Wikipedia, the free encyclopedia