This happened to my gf who is a cashier in a small supermarket.
There's this old lady (L) who always comes in just 5 minutes before the store closes and she likes to take her time (around 20 minutes each time).
A few weeks ago my gf already closed her register (the only one) and her boss (B) locked the doors when they suddenly heard someone knocking. Of course it was the old Lady.
B: We are already closed.
L: But your lights are still on.
B: I know but we already closed our register.
L: I still need to buy my stuff!
Because the store needs every cent they opened the door for her and let her do her groceries as an exception.
10 minutes later my gf leaves the store and goes to a different store (which closes 30mins later) to buy some food and guess who she saw there - the old lady once again. She does this all the time.