What is sad is that I did that very same thing some years ago. But I turned around and went back to the station and gave them back the hose and nozzle. The guy couldn't believe that I came back, said that I was the first person that owned up to it. Told him to bill me the cost and he said "not to worry about it, that it happens a lot more than you think". I lucked out on that blooper.
Sad to say but that might have been one of the leave without paying thieves. Down here it's an automatic license suspension for leaving without paying. I guess that depends on the station getting the tag number, though. Some stations (more and more) video record the pumps. With prices this high it happens - usually caused by the vacuum where a brain should be on the attendant's part.
Probably like Brian said though. Like making a pot of coffee without the carafe in the machine. I get really tired of cleaning up that mess.