And then you tell them "well, thanks for the free ride" and you walk away. I've never had a cab driver balk when I use that and the machine immediately starts working again.
Got in a shouting match with a cabbie once in Chicago for this same thing and when I opened the door to get out after he insisted repeatedly his machine wasn't working, he threatened to kill me if I didn't pay. Then, when I threatened to call the cops, his machine immediately started working.
You mean you stuck around to find out it still worked?