The SFO trip was this morning. When I arrived around 11 AM at the international garages (A and G) all the L2 chargers were occupied. I drove back and forth between the two garages a few times, and the cars were not moving out. On closer inspection, probably 80% were not charging at all, as they were fully charged already.
The drivers who park their cars there are charging for free, and probably take the nearby BART into the City, and abandon their cars all day long. I walked around and unplugged any car not charging. A couple of them sounded their horns.