Who is excluded by default and why? anyone who is not at the top of the privilege pyramid is excluded because of an oppression-based social structure. People of color, women, disabled people, non-neurotypical people, poor people, queer people, trans people, etc. When you are excluded by default, you know that most spaces will not be inclusive of you because they will not be safe for you. People will use slurs that attack you, they will expect you to speak for 'your group', they will either ignore your existence or only talk to you about your difference from them, they will make plans that you cannot do because of a disability or lack of funds, they will use language that erases you, they will ask invasive personal questions, they will not provide accommodations nor try to fulfill them on request, they will touch you without permission, they'll expect you to be 'socially appropriate' and judge you if you get socially anxious and go quiet, or if you stim, or if you fail to laugh at their stereotyping, etc.
A great example of missing the point is when the local burner community came together to create an all-terrain powered wheelchair for a disabled burner who is very active in the community. This was so beautiful -- and yet they didn't appear to consider other people who might also need an all-terrain personal vehicle in order to get around at a burn. They didn't appear to consider changing the venue so that all people who use wheelchairs could more easily get around. To be fair, I didn't ask, maybe they tried finding a more flat/accessible place to host the burn and couldn't (was there even a ramp to the showers? or an accessible portapotty? I don't remember, because I didn't need it <- privilege). But see, while this was generous and loving, it wasn't radically inclusive. It did not fix the greater problem or even discuss it (at least, not at the fundraiser I attended).
I value radical inclusion, which is why my house runs on these house agreements. I want people to know that they absolutely are included, right up to the point where they start excluding people by making the space unsafe. I want them to know ahead of time that they may have their behavior critiqued** (and that they are permitted to critique others including me). And I feel that if the burner community required people to agree to a code of conduct before buying tickets, and then kicked people out for not abiding (one warning, MAYBE two considering), they'd be about 500% closer to radical inclusion. And I would self-select in, for one.
One thing that is probably not possible for the organizers to get people to do but IS possible for individuals to do is to self-educate. So many of the exclusionary behaviors I mentioned come from sheer ignorance. If you have no access to the internet or spare time to read, then it's not on you, but if you do, and you fail to self-educate, you are guaranteeing that you are going to make someone feel excluded. The only path to making everyone feel included and safe is to learn what makes people feel unsafe and stop doing it.
* some individual burners do live up to them magnificently: I'm talking about broader trends.
** I really need to get better at this. Luckily my friends are better than I am and usually speak up when there is a language issue or something, but I freeze for like two minutes and have a very hard time bringing the focus back after I unfreeze. I know practice will help.