Why is that even a concern? If you have a hard wired charger (versus a mobile charger) and somehow manage to convince the car to drive away while plugged in, it's not going to pop free of the wall like a regular cord anyways...
Seems like a rule that was made up by someone who doesn't actually understand how EVs operate and also that the rule would often be irrelevant (fixed chargers). Unless secretly all the wall mounted/etc chargers have break away cables that nobody has mentioned?