Thwok speaks the truth.
And damn right they should demand payment up-front too.
It's only the same as if I were to fill up at an Esso garage and tell the bird in the kiosk to 'put it on my card'.
I don't have an Esso card.
But then I think the CCTV footage of a Jet2 drive-off at LGW would be amusing. I think the big 'Jet2' lettering would give it away.