Earlier quoted context omitted.
What if students (or whoever in a power sharing dynamic) are making decisions that are bad for them? How do you veto a bad decision?
I've also worked a fair amount with "alternative" educational structures, albeit in a different country (France). In those kind of pedagogies (mostly Freinet for me), the adults ultimately do have a veto power. However, when you give kids responsibility, something funny happens - you find that they tend to become very reasonable, and you very rarely have to use veto power. More often than not, it's more renegotiation…
One of my friend's daughters is vicious at this. At 14, for a "career and personal planning" project, she stated career her goal as "porn star" and somehow wrangled a skype interview with a 19yo "mentor" in the biz. She has no intention on following this path, but loves how it drives teachers up the wall. "If billy can want to be a soldier and kill people, then I should be allowed to pursue my dream too." She's a perfectly normal girl, but once she identifies an authority figure as weak she turns them into toys. Put her in a free environment and I'd expect resignation letters within the week.