I think the point is that you turn up at the charger - put your card in and say "bill me for the time I'm here", and someone else comes along unplugs you and put it into their car - you pay for their time and don't get a charge!
If the plug was locked while charging that'd be something, but then when you're 100% charged, you'd really like it to unlock so someone else can have a go with it.
Its a tricky thing that will require a fair bit of thought to get right. Until then, I will buy the popcorn and go watch the hipster 'fights'. Think there's money to be made uploading the videos to youtube?