Something like this actually happened to a former colleague of mine. They installed a safety rail on their front porch. Someone complained.
Maybe in the cabinetry case there was a giant van with a company logo parked out front.
Either way, permits shouldn't be required for non-disruptive (and a van being in someone's driveway is not disruptive), non-structural changes to a house.
I’m aware that zoning and permitting laws have been an issue for a while (like a lot of Millenials I haven’t been able to afford to buy a home), but it does feel a bit authoritarian for the local permitting office to look for signs of “black market” modifications to one’s own property.
Most places like not places like Oakland, Berkeley and Santa Cruz County, this sort of thing depends on the neighbors. It's inane what neighbors will go running to the city for. Or not. Friend of mine in the east bay completely gutted and remodeled his house no problem. In San Jose neighbors complained to the city about a disused dishwasher in my garage.