Not to mention that it's also somewhat untrue. While the fumes of gasoline are flammable, gasoline in liquid form is not. I was working on a film at a gas station when one of the crew was smoking. The guy saw the owner of the gas station walk by and remembered himself, apologized to the owner, and put out his cigarette. In response the owner proceed to light a cigarette and then flicked it into a puddle of gas on the ground, where it sizzled and went out in one of the most bad ass ways to prove a point that I've been fortunate enough to witness.
It was only slightly ruined when the owner told him that he probably shouldn't smoke on set for other reasons. But still.
Gasoline (in liquid form) definitely is flammable. However, like all forms of fire, it needs oxygen, and only the gas at the surface is exposed to oxygen. In the incident you described, the gas probably burned off before it reached it's flash point.
Gasoline vapor OTOH is combustible. If you surround a flammable molecule with enough Oxygen for it to catch fire, but still close enough to the surrounding molecules that it can ignite them, then you have something that's explosive.