'No-tailgating' is really, really hard to enforce. I work in a shared office building with a keycard door, and people are genuinely surprised and angry if you d

'No-tailgating' is really, really hard to enforce. I work in a shared office building with a keycard door, and people are genuinely surprised and angry if you don't hold the door even ­if you don't personally know them and can't vouch for them (which is most of the time). It is a really strong bit of social conditioning not to shut a door in someone's face! So during security audits you can now tick the box that access to the premises is secure, while in reality anyone can just follow random people in. Now carry a box that requires two hands, wear a lanyard with a card hinting at being some kind of courier, and not a soul will stop you unless the building has actual security.