Hey Sport Pilot... Based on the last three post you made I have to comment. You stated that the aviation industry continues to make outdated and unsafe products, I beg to differ. I have been in the maintenance field in aviation for more than 30 years and somewhat agree that product technology is outdated but... is not unsafe. I do know first hand that if an airplane or related system is PROPERLY maintained failure is unlikely.
Your comment about magneto switches, which is what this thread is based on, we all agree on. I have never heard of, read about, or seen an ignition switch fail in the air. (Magneto's occasionally do, but it is rare) As I said in my post #6, there are preventative measures in place, aka, AD notes that address this issue and when performed properly at the stated interval are usually a non issue. I have replaced several bad ignition switches due to bad key/lock mechanisms, never due to an electrical anomaly. Aircraft ignition switches merely provide a ground path for the magneto's.
As a safety check I do for every inspection, whether or not it is required by an Airworthiness Directive, is with the engine idling, switch the ignition off to assure the engine quits. I have seen a number of broken grounds at the magneto that without this check makes for a dangerous situation. This is commonly referred to as a HOT MAG.
-Tom