Over the weekend, Commerce Secretary John Bryson ran into two cars while driving in LA. The official claim is that he had a seizure which made him unable to control his car.
Regardless of what really happened in Bryson's case, as far as I'm aware it would be just about impossible to refute a seizure claim. If he had alcohol or vicodin in his system he might be screwed, but otherwise, he'd likely get away without any other trouble. Some people with a seizure disorder have abnormal EEGs and MRIs and such, but some don't.