Using that technique, and relying on the fact different users are going in different directions, demand can be shifted to other sites hundreds of miles away and many hours into the future.
You can also shift demand onto users home chargers (make them arrive home with less charge).
Most of the time, the vast majority of your charging should be at home. For edge cases like this, well, it is pretty cheap to build out charging infrastructure at any highway rest stop.
Longer term, there are plenty of possible solutions with an SDV public transit system.
You say "Recommended charge time: 15 minutes. Any stay over 25 minutes will be charged an extra parking fee, or you can move the car to a non-electric parking space for free.".
You don't need every user to obey - just ~half of users following your recommendations should keep enough spots free for more incoming cars (which Tesla can predict pretty accurately ~an hour into the future)
By the way, I think with how fast DCFC is becoming, we are currently in a weird situation where there's still time for people to have a meal. In the near future, charging would be so fast that you basically have to stay with the vehicle.
Well, that assumes people leave the vehicle.
What more frequently happens is there is someone in the vehicle doing work, watching Netflix, sleeping or whatever.
When the charge is done, they take 10 seconds out to unplug, and then go sit back in the vehicle.
When using Tesla nav and needing an SC mid journey, Tesla notifies on screen and notifies via the phone app to leave as your state of charge is enough for next leg of journey. Likewise when using built in nav and catching a last SC leg of a trip, it by default has you arriving at low SOC% too.
Likewise, it's advantageous to have a home charger and use it purely on cost in my experience. I haven't encountered any daytime SC cost that was cheaper than my home power cost.
[edit for clarity] Tesla does penalize for sitting on a charger, plugged in, after you've reached your charge limit set.
Or dynamic rates so some areas get cheaper and peak areas more expensive? Might get accused of profiting from surge prices. But might allow people who can shift where they charge to help spread the load.
Or create a secondary market. Rent out your home charger. Booking app.
Usually queues are obvious where it's 1 way in/out of a charger block. I've found it's up to the first in queue to establish and 'defend' the queue though. Many times folks charging know and nudge / wave / flash lights at the actual next in queue while slow rolling out for them to get in.
Very common for those queues to be obviously double park or line up idling if there's enough room but again depends. The worst locations are where there's back to back rows and both row ends have entrance/exit. Common at Target or other SCs in very large but not long lots. Where, I've seen a queue form on both ends.
Having to fight for a charger spot, and potentially queue for 10s of minutes, and then wait tens of minutes for your car to charge, and be ready to leave when you're told to... Nightmare.
Hopefully the situation will improve quickly. If not, my next car will be a plug in hybrid.