The rear entrance door is one of those that unlock when an employee holds his or her access card up to the card reader. As the group single-files through the door, I fall in at the back of the line. The guy ahead of me reaches the door, notices there’s someone behind him, takes a quick glance to make sure I’m wearing a company badge, and holds the door open for me. I nod a thanks. This technique is called “tailgating.”
