Here's another argument people can probably stop trying. The California Court of Appeal ruled on February 25 that a drunken passenger who caused a car to crash could be convicted of "driving under the influence." The defendant had argued that the statute did not apply to her because she had only grabbed the steering wheel and so technically had not been "driving."
California law defines "driver" as "a person who drives or is in actual physical control of a vehicle." Cal. Veh. Code § 305 (emphasis added). There is a specific exception for the dude who gets to steer the back part of a fire truck, who is apparently called a "tillerman," but otherwise the law is broadly written. The only cases citing this law found that the definition covered people who were (1) pushing a car, (2) towing a car, or (3) opened the door of a parked car to the sudden detriment of a passing cyclist. The argument seems at least plausible in all of those cases, and yet it failed.
So the defendant's argument here was at least a long shot. She had been drinking and admitted she was arguing with the driver (her boyfriend), when she angrily grabbed the steering wheel and yanked it. Doing this when a car is moving is generally not a great way to make a point, unless the argument is about whether yanking the steering wheel will actually cause a car to crash and roll over several times. Because it will settle that particular argument.
As for the wheel-grabber-not-a-driver argument, it has failed before. The court cited no fewer than four cases from outside California holding that a wheel-grabber was in "actual physical control" of a vehicle (if only briefly). There were no California cases on point, but, remarkably, there have been two cases in which two intoxicated persons have agreed to drive a car in tandem (or try to, anyway), with one behind the wheel and another working the pedals, and then later tried to argue that neither one was "driving." In both cases the argument worked as well as the driving itself did.
Finally, the defendant also challenged evidence that she had committed two unlawful acts (in addition to being drunk) by both interfering with the driver and making an unsafe turn. Aha, says Defendant: if I was driving as you claim I was, then I couldn't have "interfered with the driver" because I can't "interfere" with myself; and if I did "interfere with the driver," then I wasn't the driver, was I? So if you'll just remove these handcuffs, bailiff, I'll be going now. Hello?
That was "a poor attempt at sophistry," the court said, being polite.