It seems like a small lecture on airbags is in place...
The sensors that detonate the airbag in modern cars are placed inside the front crumple zone and deploy when the velocity of a crash is around 20-odd kilometers per hour. When hitting another car, the crumpling of both cars and the tendency of the other car to get pushed away will result in the airbag remaining undeployed unless the force of impact is around 30mph or so. When hitting a solid and immovable object head-on, it could deploy at speeds of 15mph or so. Spontaneous airbag deployment can also occur, but has become rare in modern cars.
The airbag only deploys after the initial crumpling of the car's body and after the pretentioners have done their job. At this point, the engine block and/or front axle will hit the obstacle and the force of impact would push the upper body of the driver forward, at which point he or she should meet the airbag as it deflates.
During this process, various hand injuries can occur. The hands can be thrown forward unto the dashboard or front windshield from the force of inertia when held too low, they can be thrown by the airbag and in lateral collisions - hit the door and/or the driver's ribcage (Again, when held too low). A jerk of the wheel can also lead to finger injuries, but this has turned rare.
Airbag-related injuries are also various. This includes short-term respitorial problems and burning eyes from the dust, ringing ears and problems with glasses, cigarretes and arms that might be disludged at the interior parts of the car or at the driver/passengers.
These injuries depend on the volume of the airbag (which varies dramatically from 30 to 80 liters, with bigger airbags used in american cars, as a consideration for unbelted drivers), and the position of the body and hands relative to the airbag. In modern cars these injuries can be prevented or reduced by using several detonators to vary the power in which the airbag opens.
Modern airbags cause less conflict with eyeglasses and if they do shatter them - than the alternative would have been a broken skull and brain injury. Hand injuries are also reduced to either minor burns on the forearms or by having the airbag deploy in a triangular pattern that pushes the hands down against the thighs, provided that they are positioned low enough across the wheel.
Hands in high positions or across the wheel can hit the driver's face, the passenger's face, the door, window, windscreen, A-pillar and even the roof. I still believe that in this case, primary safety cannot be compromised for the sake of secondary safety - and that the driver's steering hold and steering style should not be limited to the lower portion of the wheel or to it's sides, but rather remain natural and keep a wider range of motion available to the driver.
When it comes to the initial steering hold, a quarter to-three position is ideal (except when there are problems with the driver's stature) since not only does it not cause conflict with the airbag but it also provides a better grip and wider range of motion. Adjusting the steering so it is at least ten inches away from the sternum and with the palms holding the wheel placed four-five inches below shoulder height will improve both aspects of safety, also.