The only effect of a Code of Conduct I have ever personally witnessed was that people were being bullied for greeting others. The greeting they used was "hey guys", and instead of recognizing that language is fluid and different to different people they tried to impose their linguistic views on others. The people who encouraged this behavior were people on the Code of Conduct committee and at the top of the project's hierarchy, and to this day nobody has apologized for this behavior, but the behavior was silently dropped.