Operating Hours

At the door of most businesses, there’s a sign like this:

Operating Hours
Mon-Fri 9AM to 7 PM
Sat-Sun 10 AM to 6 PM

¿Are these the hours when customers can do business?
¿Or are these the working hours of the employees?
A customer that arrives at 6:59PM expects an establishment open for business, not an employee locking the doors of a dark store.