I don't get how people get in this situation. I'd never get down that low on the way to a supercharger. The car tells you how much you have, where to go, and will automatically re-route if you're running low or the sites are busy. The information available to drivers is excellent, and you can see how busy chargers along your route are getting, and use common sense to deduce that certain days of the year will be super busy. Then you adjust your route or charging to compensate, eg, stopping to charge earlier than you need to if there's a quiet charging site, and putting more in so you can skip your original choice