It has been argued that it is in the best interests of IT professionals, to adopt and enforce professional codes in the work place. But there is no code for usability engineers, unless one accepts that it is a branch of software engineering. The new joint ACM/IEEE-CS Software Engineering Code of Ethics is applied to actual usability cases. This enables usability engineers to interpret this code in their profession. This is achieved by utilizing four case studies both directly in terms of the ethical issues involved and in the light of the code. Also examined are the short-comings of the code for the domain of usability engineering, and suggestions are made for enhancements for future revisions of the code.