It's not just GM with bad ignition switches!

Even my off-road toys have ignition switch issues. These are caused by vibration and environmental exposure but the result is the same. It comes down to the fact that the manufacturers engineer the switches to set a set of parameters that does not always reflect real world use resulting in premature failure. In the case of these automobiles, the tumbler assembly was not designed to handle the load of a heavy key ring resulting in intermittent electrical contacts or unintended position/function selection due to mechanical slop or weak detents in the assembly.