Sister

I was talking to a customer the other day and she asked me why I use the word ‘sister’. She thought it was inappropriate for me to call a lady ‘sister’. Now, what I want to know, by checking the box yes or no, do you think that I was inappropriately using ‘sister’ or is that word commonly used in this situation ?
Whatever the case, this sister was a black woman, whom at the end of the day purchased a Street Sense. So, it goes to show that people have a different set of rules of how you should sell the paper. It’s almost as if they want to teach you how you should sell the paper without doing the work themselves.