Good points ojh. There are certainly decisions to be made regarding mechanical vs electrical reliability. Things do break. That is why I never rely on the neutral safety switch when starting up and always make sure the handle is in "Park". Last year at Sacramento Raceway, a dragster started up and started running in reverse breaking a young boys leg in the lanes! Fortunate it was not worse. That was a mechanical problem. I do use relays, such as the one that powers my Holley Black fuel pump. It goes out - no race today! Regarding the mag relay, it must be on the non powered side, as the power is what holds it open (mag not grounded). As for starting, when the safety switch is activated, no 12V power to the starter means the engine will not start, even if the mag is not grounded anymore. Although, I guess it could be "push" started.
I am mostly interested in the darn thing working in the event of an accident. And, Flaming River, at $110 for a switch has certainly proven that cost is no predictor of reliability! And that stupid thing is a mechanically activated switch, making an electrical connection!! Go figure!