In an employee-first company, as you listen to your employees (or associates) they will listen to customers.  They should notice that something wasn't selling first and begin taking action to address the problem.  If you truly look out for your people, they begin to be freed up to look out for customers.  Employees will grasp pretty quickly that "good" customers are the key to their own self-interest.  They will be working to help you understand what the customers want.  They'll invent ways to provide quality service for "good" customers.

It's a bit less clear in retail, but as you know, "bad" customers can be pretty unrealistic.  Unrealistic or obnoxious customers cause the majority of the problems.  If your company produces quality products and provides quality service, those customers stick out like a sore thumb.  Then, it's up to the leadership to keep those problem customers from killing employees.  Employee-first simply means having the intestinal fortitude to make sure that profit never trumps people.  The highest, best purpose of a company is the lives it funds.

Thanks for the great comments!