The pump doesn’t auto-start when you unhook the nozzle from the pump. I think the cashier has to manually allow it to start, from their control system/computer.

So I suspect they wouldn’t let it start if you look shady (hooded, no plates) and they suspect you may run it off.

For example if you ride a motorbike, the cashier sometimes doesn’t start the pump until you uncover your face (allowing cameras to see your face).

But otherwise, we either pay at the fill-up then go pay at the desk (yes they can be a waiting line if there are more pumps than open cashdesks) or pay directly at the pump by card/contactless (modern pumps). It locks a sum on your card, say 200EUR, and when you hook the nozzle back it adjusts the payment transaction to only the amount consumed and debits you.