@dragonwriter has it right as far as the pro-UBI position being a varied one. I recognize that mine is nonstandard.
In general, I prefer:
1. a functioning government
2. a UBI-enabled market
3. a malfunctioning government
It seems to me that the least violent way to kill off a government and bootstrap a new one in its place is to work towards a position where you can safely turn your back on the currency that the incumbent is minting. I view UBI a tool to make such a step more palatable. A safety net for transition times.
It still has to be backed by something, and I think the most likely candidate for that something is demonstrated success in other areas of DIY-government. If people can look around and see that the problems are getting solved, then maybe they'll have enough faith in a UBI system designed to let them safely quit the old ways and participate in building something new. This credibility would come from solving things like education and healthcare, which is why I say I have a hard time imagining a UBI system getting up and running in a community that does not have a grasp of those more immediate problems.
Without that initial success as a credibility-builder, the UBI-paved road to a functioning government will be indistinguishable from a ponzi scheme: here's some pretend thing for you to value.
If people truly have no faith in the existing government's ability to do government things, then their DIY efforts should be gathering steam to sideline that government, not angling for a slice of the tax bill from the very government that they've lost control of. If they get that slice they'll have become the very sort of corruption that they're objecting to.
If that's not an amount of work they're ready to stomach, then maybe they should rethink their disavowal of the existing channels in the first place and instead go participate in them.