This is hilarious but there's no way in hell they'll be able to extract rent. They'll get their 90K back and a note from the mayor or something and the Presidio Hieghts owners will have to pay up in donations to Ed Lees campaign or the local district supervisor.
... this is very basic and fundamental property law. They now own title to the common areas. No mayor is going to be able to overturn property laws which have developed over hundreds / thousands of years.
There'll be an apology for "accidentally" doing the paperwork wrong, which a judge will say nullifies the sale.
Alternatively, the couple will just be sued for lots of random things, and will run out of cash defending themselves, forcing them to declare bankruptcy and sell the property.
A handful of "rich and powerful" people lost out here. Orders of magnitude greater numbers of "rich and powerful" people rely upon unassailable precedents of property law to "take advantage" of less sophisticated people every day. Nobody is going to risk overturning or weakening those precedents so that the first handful can save a couple million dollars. Just like most ballot initiatives in California, these battles are rarely "rich versus poor" but rather "rich versus rich".
The thing is, those people stay rich and powerful precisely because of the sanctity of property titles.
And the city's own incentive is to be as harsh as possible toward unpaid property taxes. The quotes in the story from Jose Cisneros are consistent with this.
So even though the residents are wealthy, they are up against powerful institutional forces.
And while it's absolutely true that the legal system favors the wealthy, there are diminishing returns to being still wealthier. Beyond some point you can afford to have a competent lawyer on retainer and it's much harder to simply bury you in trivial stuff. It's not obvious that these real estate investors will be easy to push around.
I predict that unless an obvious loophole appears very soon, it will be cheaper for the homeowners to just buy the investors off.