She tried to bargain for something and said she had been buying from the shop for over 30 years at their first outlet.
The staff told her they no longer allow what the lady requested as they want to treat all the customer fairly.
Can you treat all customers fairly?
There's a difference between the definition of fair for you and your customers. Customers do not want you to compare them to the next customer and say that what's fair to other is fair to them.
How can you treat all customers fairly without them feeling unfair?
Treat them differently.