With all the stalk-mounted controls on the steering column, the ignition key isn't that out of the way. I don't know about this GM car, but in my toyota, when reaching for the cruise control with a gloved hand I can jangle the keys.
The ignition switch is separate from the “key lock cylinder”. The ignition switch is located on the steering column beneath the dashboard. I believe that jarring and/or wear can effect the internal contacts of the old style switch causing a break in continuity. This may or may not be associated with jarring of or dangling of weight on the “key lock cylinder”.