72,
You keep missing the point. Nobody in their right mind purposely leaves lug nuts loose. However, people get distracted, called away to answer the phone before fully tightening the nuts, have other things on their mind, whatever, & the nuts are not properly tightened. These incidents are what LH threads are for.
Wheels, both L & R side, have come off cars while being driven because the nuts were not tightened so it does happen.
As for the over torqued broken stud........
Obviously you know you have a problem...& you will be getting the bus home....