You're right in that no specific instance brought about our code of conduct. However, as I pointed out in my blog post on the subject http://overtheair.org/blog/2015/03/code-of-conduct/, that doesn't necessarily mean that harassment or the equivalent hasn't occurred. Many of the speakers that I wanted to bring to the event this year mentioned on Twitter or elsewhere that they preferred events that had them, or that they would not speak an event that didn't have one. And I felt this was a reasonable request. I think having one and mentioning it in a blog post early allowed us to bring more female speakers to the event, which in turn led to better diversity in attendees (which is always a primary goal for me). If the presence of a code of conduct is making people feel limited in the ways you suggested above then all I can say is that wasn't the intention. Maybe it's possible to craft the language in a better way, or in a way that takes into account the UK's historically more risqué approach to humor (which is one of the things I love about the culture here, by the way).