IDEA: Keep customer / vendor shared information always confidential.

Instruct all employees with access to private outside customer information to always treat it confidentially. That information is to be kept confidential and not shared with anyone or any other department. Only court orders requesting information are acknowledged and run through the corporate legal department.  Company financial information sent to your company used to make credit decisions is always to be kept confidential, exactly as you would want your information sent to vendors asking for credit. It is expected to be confidential. Teach your employees you do not need to get sued.