[ispolin]

Neither. In US, your plane has to have the 6 basic instruments to be certified as airworthy by FAA. The reasons pilots die in non-visual flight conditions are twofold.

As the original article pointed out, the first reason is that the sensations are so compelling that doing what the instruments tell you will feel VERY unnatural and you will keep thinking that your instruments are broken or stuck (hence you HAVE to trust your instruments). And even if you remember not to trust your instincts, you will still often unconsciously apply slight pressure to the controls.

The second reason is that for every change in the plane's orientation and speed, several instruments will start moving at once. Without training it is very hard to integrate what the 6 instruments are telling you into a complete mental picture of what's going on with your airplane.