Two lads on one scooter roll in and he asks them to come to the till first. So they ride off. They clearly had no intention of paying when they came in.
It does happen with cars, but they cannot escape so quickly through dense traffic. Some service stations round our way have prominent TV cameras with prominent notices saying that they record customers and vehicles.
With a big garage where the staff cannot necessarily see all the customers, they have to have a simple strategy. Sad times...