Cabbie21
These days so many car parks want you to input your car registration number, or use an app, so it is simpler for the car owner to see to this. Many machines only take cards, and in general, it is harder to get cash. So other ways of thanking drivers are useful eg paying for their meal. But motoring is costly, and if you are using someone’s willingness to drive, a financial recompense is due. Just need to find the best way to do it, and drivers not to be taken for granted.
When this thread started several years ago, cash payment may have been the norm.