What is wrong with some of you people? The keys do not and have never "fallen out" of the ignition switch.
The issue is if anything heavier then one key (according to GM not me) is put on the key ring and you hit a bump the ignition switch can and DOES rotate out of the RUN mode! This turns off the vehicle disables the air bags and seat belt tensors, you lose your power steering and brakes. For a full grown man this is not and issue, for a young teen male or female and most women, this is a oh-$hit moment. It can and HAS caused at least 13 deaths and GM has known about it for a very long time and did nothing to fix it!
Don