When I was a kid back in the late '50s in Arkansas, I made some extra bucks in the summer by mowing lawns. Down the street was a Conoco station, and the owner knew me well, since I picked up my newspapers for my paper route there, and as his was the only gas station around, I bought all my mower gas there.
I would often wheel my mower into the station for a tank full of gas. (It was easier than lugging around a gallon can!) On several occasions, the owner, rather than pump the 7 cents of gas that would fill my mower, would do just what Heidi has been doing - put the pump nozzle into my tank and open the valve. The remnants would flow from the nozzle and hose and fill my tank. Well, it might have taken a couple of hoses worth, but he wouldn’t charge me for the gas.
Now, back in those days the pumps didn’t have vapor recovery systems and breakaway fixtures, so I suspect it was easier to get a significant amount of gas from the hose this way. Nonetheless, the practice - engaged in by the owner of the station - helped this youth put a few extra coppers in his pocket on those very, very hot summer days.