You joke, but they can partition off a small space, rent it out, and claim they are renting the entire thing to someone. It can be a housekeeper who actually has access to the entire thing.
They can also split the property into multiple independently owned properties that just so happen to be right near each other, each just under the limit.
If the housekeeper gets to live in a $5m penthouse downtown instead of a walkup with a 60+ minute commute, I'd file this as an unintended win for this policy.
They can also split the property into multiple independently owned properties that just so happen to be right near each other, each just under the limit.