The problem may not be perpendicular parking as much as fitting two cars in one space. In both photos with the SF article, I believe the Smarts were occupying a metered space that was already taken by another car.
In the neighbourhoods where I am outside Cleveland, I often find someone has missed using the space between drives efficiently and there isn't enough room for a second conventional car. A Smart can easily optimise parallel parking without a violation. If you are parking in a community on a regular basis, check the local ordinances and get an opinion you can refer back to if you have to protest a citation. i.e. in some areas, you may be required park in the direction of traffic, if you're coming from the other direction and pull into a space, you could be cited. If there's no ordinance against this, you may still be cited and then you must bring the issue to the attention of the local police to get the citation cancelled.
Until there are more Smarts and the questions have been raised and answered repeatedly, the awareness among the enforcement community may remain low. But I know that here in Cleveland, a local article noted that putting two vehicles in one [metered?] space was an issue and perpendicular parking could also net you a fine. I don't recall whether the act of perpendicular parking was the violation or the revenue issue was the driver.