I booked in advance and paid by credit card. When I arrived at the car park I was confused about what to do: it was very unclear I had to stick the credit card itself in the reader. I have seen cheaper parkings using a number plate reader. Anyway, I got trapped while trying to exit. Apparently you can't just stick the credit card in the reader again, and as you have no real ticket you must press a button to contact their customer service and tell them your reservation number with other cars waiting behind you. Mental. I ended up shouting at the customer care rep because she wouldn't let me out without checking (for 10 minutes!) my reservation number. Ludicrous: avoid!