Tesla should have a system where once all (working) superchargers are occupied, the supercharger will refuse to charge beyond 90%, and then there should be some Level 2 chargers available nearby for those who need it.
There is a level 2 charger at Harris Ranch. I have never seen anyone using it. When I saw it, it had a Roadster adapter hooked to it, as it is a Roadster charger, but usable. It is also over by the Subway sandwich shop, so I wonder if most people even know it's there.
I wonder how many people would move their cars at one hour (80% of charge) to a Level 2 charger, just to be nice. NICE? Not very many people think of anyone else wanting or needing a charge, or are aware of the fact that chargers ramp up and down and at an hour, the charger has really slowed down. Heck, most people I meet don't know the chargers are paired, and will pull into a paired spot next to the only other Tesla there.
Basically we need education. What signage might get people to understand any of these issues? How many of you put your cell number on the dash so people can call you if it's crowded and it looks like you've been there a while? Sure, you only PLANNED to be there 30 or 40 minutes, but.... Last time I was at Hawthorne, at least the guy getting a full charge was sitting in the car.
During the RAV4EV years, people were putting Charge Cards on the dash, with time charge started, estimated time of finish, telephone numbers, just about everything you would need to know. But there was always that small percentage (as I remember, it was about 80%) who never remembered to use them.
I have no suggestions. We are dealing with defective humans. And we're all defective. Thank goodness we are not relying on using 10 kWh chargers like we were then, waiting 4 or 5 hours to get enough charge to get back home. At least now it's only an hour or so.