The obvious reason for bringing up the fact she was a teacher is that regardless of profession, be aware of who is in contact with your children. 
Secondary would be that more people recognize her as a former teacher rather than a  former customer at Dairy Mart, unfortunately most criminals are not caught the first time. Other victims may come forward in the future. I hope she didn't. Lastly I believe that if other teachers school worker's become implicated and full light isn't shed or future teacher, ex teacher allegations are covered up it's a dis-service to children.