Somehow my newsfeed is always popping up articles about public charging stations, including reddit and other "forum" conversations. While the few public charging stations I see in my region are empty more often than not, apparently in urban areas the lack of them is already an issue.
I guess there are ecar drivers who will pull up to a charging station, plug in, then take off for hours to eat lunch or shop or whatever. There are ongoing debates on if it's acceptable to unplug someone else's car to charge yours if the other car's owner has disappeared. I don't know if there is some way to look at the charging station to see if the other guy's car is fully charged or not.
Seems like if you want to prevent people from taking off after they plugged their car in, you'd need fast chargers that are 5min or under, and that may not even be possible. If charging takes 15min or more, there are simply always going to be people who take off and do other stuff for an hour because they don't want to stand there for 15 minutes or more. Maybe an app that alerts you when your car is charged, but then you have to count on the person being polite enough to immediately return.