Ignition Switch problems of the 2004 Chevrolet Corvette

I was driving on a highway at 65mph in a bumpy construction zone. All of a sudden, without warning, the engine completely shut down. I was able to steer the car off to the shoulder of the road. After letting the car sit for a minute, I was able to restart the car and immediately drove it back home on a surface street and took it to the dealer the next day. The dealer put it on the scope and could find no problems with the car. The only thing I could think of was that I had a medallion on the key ring and the service manager advised me to only keep the ignition key on the ring because the swaying of the key chain may have affected the ignition switch and turned off the engine. Based on the recent info on keys swaying and cutting off the ignition to the car, I was wondering if it affected the Corvette models also. I only keep the ignition key on the key ring and haven't had a problem since that time.