I worked at a retail office store that did printing too and the amount of people who would regularly show up right before close, and stay late like it was no big deal was astounding. Even after being told countless times by managers and employees that once it's close time, they have to go. The regulars would get reminders, people would let customers know of the "we close in 10 min" and they would still stay past all the time.

If someone forgot to lock the doors people would walk in 10 min late, and then get angry, sometimes even irate, that we could not service them as machines are off and registers locked out for the day when we explained we are already closed. I worked there for 3 years and this happened many times.