a government wouldn't be formed if people in an anarchist situation didn't want there to be one. presumably there would be some understanding of what creates on-going, static, power imbalances, and people would avoid those, as much because they don't want them in the moment as because of any future consequences.
if one group of people wanted power and were serious about it, other people would have to fight them (there are various means to fight, of course). i for one don't think there is any way (nor would it be desirable) to try to create some rule set or institution that would oversee folks to prevent a government (or state-like body) from forming.
(there is an interesting, fun short story by philip k. dick that talks about roving anarchists who search out hierarchs to get rid of them. it's called "the last of the masters.")
