Meno and Ubiq.: From a statutory analysis standpoint your interpretation of “fixed obstruction” is ludicrous. A lawn is not a fixed obstruction by any reasonable interpretation.
Further, while an approved permit is likely, on it’s own, a sufficient reason to assume a “driveway” is “authorized pursuant to applicable law” it is not the only “applicable law” which is relevant. Thus technically, even with a permit, a driveway can be unlawful, and even without a permit a driveway can likely be lawful. Property law is complex, and simplistic statements as to the lawfullness of driveways do not appear to be accurate.
Towing or a ticket can occur if the relevant authorized party has a reasonable basis to believe that 408f2 was violated – even if it was not. Thus, parking in front of any curb cut should likely be avoided if possible and may result in annoyance or worse. That is my opinion, which is supported by a reasonable interpretation of the relevant municipal code and rules.