Far more than security. Most of society is built on the honor system.

In half-full bar at an hour when there isn't a bouncer (usually before 9pm in NYC), the only thing keeping twenty or thirty people from pouring their own booze for free is a large slab of wood and a person behind it. The name tags and maybe a counter do the same thing at a retail store with one or two checkout people.

Society is almost entirely built on a simple trust system and the fear we've built into ourselves of the repercussions for going against societal norms.