Is it possible that your fuel cap was on properly secured? Like one of the tabs not engaged?

I made a left turn one time on a full tank. The police car behind me turned on the blue lights. I was certain that the light was still green. The officer said that I had not done anything wrong, but he observed gasoline spilling from my fuel tank when I turned. (I assured him that he did not see any gasoline spilling from a 300D!!!) But I did find that the fuel cap was only partially engaged, and fuel was in fact leaking out of the filler neck.