Maybe not to the extreme you described....
, but yes, my wife can sometimes do the same. She likes to "nap" if we're out on a trip (like, she's asleep before we get out of the driveway...) and then if she awakes with a start, for some reason like hitting a reflector when changing lanes, she jumps nearly out of her seat and screams "what's wrong!!!??" After getting my skin stretched back over my body and my heart back down out of my throat, I fight off the urge to back-hand her.
I do try to not hit reflectors on lane changes, just as an old game from my father. It does help to keep you alert on those long stretches behind the wheel.
The one hand/two hand argument is like arguing over abortion - there is no answer that will satisfy both sides. I drive, while cruising with my left hand on the wheel, relaxed, in the 9:00 position and my right hand laying in my lap, or, maybe scratching......
just under the wheel. My right hand is in a position that's miliseconds from the 3:00 position. Well, okay, miliseconds when I was young. If spirited driving, both hands where they belong.
I had a hard time at the Brumos school and had an interesting talk with Hurley about it, but I'm used to not moving my hands on the steering wheel. A formula car, which is how I relate to high performance driving, has a very high ratio steering system. Believe me, if you have your hands crossed up in a formula car, you should've locked the tires about two seconds ago, because you're screwed. So, I was therefore not used to turning the steering wheel more than 90 degrees, and have never had to shuffle the wheel around in my hands. I'm afraid I did not get used to it at the school, and got yelled at several times.
Getting yelled at by an old friend, who is a multiple winner of Lemans, Daytona and Sebring, all in Porsches, is NOT good for a racer's ego!
(no matter how old he now is)
I have practiced it incessantly, since, and have become quite proficient at the skill.