The problem with any US government plan is the lack of sound policies.
After you start with policy goals, then you can look at UBI, high-density housing, service industry staffing in the Bay Area, infrastructure maintenance, etc. together.
Having said that, the most visible problems with UBI that should be addressed (in policy. see above.) are:
1) Would it further inflate rental prices?
2) Is voting for free money the fatal flaw in democracy that this unattributed quote says, "When the people find that they can vote themselves money, that will herald the end of the republic."
Modern Greece is an economic cripple from public sector benefits for example, as are all US cities. What happens when you expand that to the population at large?
3) In this proposal, what would be the effect on the industries taxed? Would people shop out of state? Would they avoid online merchants? etc.
The political issue is that any party that promotes UBI will be accused of pandering to their base by the other party. And it's an effective argument in the absence of, again, policy.
I would go so far as to say this. The most patriotic thing that Bay Area residents could do is to finance Yang or Sanders to create a PAC to design and promote logical government fiscal policy for 10-20 years, then become the third political party for elections.