One of our car parks in town had a number recognition system. We could either pay on our way out or, register car numbers with the council and open an account. At the end of the month, the charges were taken out by Direct Debit.
I found it very useful, particularly as this is the car park next to the theatre. Getting out after a show means long queues at the machines while numbers are tapped in and payment made. However, it had to be changed as, apparently, the system goes against some regulation. (GDPR perhaps?).
Now, people start leaving the theatre before the end of the show to avoid the queues.