Mooneyboy
I agree with the point that you may be able to apply the brakes in lots of incapacitation situations in a car, but I think the risk of pilot incapacitation in a plane causing a problem because the passengers can't fly the thing, are far lower than the risk of being involved in a road traffic accident due to incapacitation of your driver or that of another road user. Just falling asleep for instance... I just think it would be overkill to stipulate no passengers in any aircraft unless you have two pilots on board, that's all.