If there's one place where motoring etiquette is crucial, it's the petrol station. Especially in the holiday season where queues are long and tempers short.

So here's the big question: if you've just filled up at the pump and there's a line of traffic behind you, is it OK to move your car off the forecourt before you go inside to pay?

The answer to that second thing is yes. Of course. Especially when you consider that modern fuel stations don't just sell fuel and in holiday time you're far more likely to go inside and stock up on road-trip essentials (or be waiting for a coffee) before you make it back to your vehicle.

So it's polite to move your car before you've paid. But will it look like you're doing a runner?

We mystery-shopped three service stations and the staff all said the same thing: "Yes, please move your car before you pay if it's really busy."

It keeps the fuel flowing, it keeps people happy and it allows consumers more relaxed time to buy other stuff (which is actually where service stations make the most money). This sounds obvious, but it really helps if you take note of the pump number and amount before you move your vehicle. It's surprising how easy it is to forget when you're rushing.

Large service stations have people watching the pumps and they generally won't authorise a transaction until they have a good idea where the previous customer has gone. And there are cameras of course. Many cameras.

The situation might be different in rural areas where it's unusually busy and there isn't the same level of staffing and/or technology. Then you might be caught in the crossfire between frustrated customers and stressed staff trying their best to prevent drive-aways.

As it happens, a friend worked as a service-station attendant in a rural area in a previous life: "We were generally small enough that we knew most customers. If we didn't and somebody moved their car before paying, we would get a bit worried. But when it got really busy it was still preferable for people to do that."

This story first appeared on The Sydney Morning Herald