Our charger has a big red "emergency stop" button with stern instructions not to use it except in an emergency. The touch-screen has start and stop buttons, the start is showing when you show up, and you have to touch it to get going, at which point the screen will tell you what to do. While you're charging the stop button is showing, and you touch it to stop, but then it tells you to touch the card to the reader to stop.
When the card reader was out of order the RFID card had to be touched to a different spot on the charger to stop - there was no stop button, and I had a panicky moment when I thought it wasn't going to stop. I was already near the end of the 10-minute grace period on top of the allowed time. I got it stopped 15 seconds from a £10 fine.
But when the card reader is working it all happens using that, including when you use the RFID card, and that responds instantly.