We had a 2009 Cobalt SS in the garage a few days ago and figured we'd see what was up with the ignition key issue. GM has pretty much recalled every Cobalt ever made due to the ignition keys clicking off on their own. When a large bump is hit, a heavy key ring is installed, or even your knee hits the key, they have been turning to a non-running position. This in turn disables all driver and safety aides, including the air bag system.
So picture you are driving along, hit a large bump, your key clicks off and the engine shuts down. The driver has no power steering, engine control, and also the airbags disable. In a panic situation, this could possibly be freaky and dangerous. We aren't discounting the loss of life or anybody who has been affected by these issues, just trying out the problem for ourselves.
The later model years were initially not part of the recall, but now GM has decided to fix them all, which is a good move. This recall includes the Chevrolet Cobalt and HHR. It also includes the Pontiac G5 and Solstice. Finally, Saturn has some of the same issues with the Sky and Ion. GM has instructed owners to remove all key rings, accessories, etc as this may cause the key to click off even easier.
What we found was interesting. The ignition key started the vehicle normally. When tugging, yanking and applying fairly decent pressure to the key, it wouldn't really turn off. Now keep in mind it was sitting in the garage and didn't have any jarring bumps or hits on the suspension. I could get the key to turn off only if I applied the same amount of pressure I would if I actually wanted the car to turn off. You will notice though, it does seem to click off just a little bit easier than it should maybe... Take a look at the video below, it shows our quick test and what we found. Either way though, if you have one of the models listed above, I would highly recommend you schedule your vehicle for service and get your new lock cylinder installed. GM has even started a very detailed website for more information - http://www.gmignitionupdate.com/