Final answer:
The term for an intruder gaining unauthorized access by following an authorized person is 'tailgating' or 'piggybacking'. This physical security breach can happen with or without the knowledge or consent of the authorized individual. It is different from identity theft, which involves illegally obtaining personal information to commit fraud.
Step-by-step explanation:
The behavior described is known as “tailgating” or “piggybacking,” which occurs when an intruder follows an authorized person through a physical security barrier without the necessary permission. Although the question mentions this could occur with the knowledge and/or consent of the authorized person, tailgating is a security breach regardless of whether the authorized individual is complicit or simply unaware. It's a common method used by intruders to gain access to restricted areas.
In relation to identity theft, tailgating does not usually involve the theft of personal identification information. However, both situations involve unauthorized access to something valuable, whether it be a physical location in the case of tailgating, or personal data in the case of identity theft. Identity theft, sometimes referred to as “True-name Fraud,” is a separate issue where an individual wrongfully acquires and uses another person's personal information, such as a social security number or credit card details, to commit fraud or theft. This may include draining savings accounts or making large purchases in the victim's name.