Explanation: In June 2009, The New York Times reported on a car accident in which one driver nearly got his right thumb ripped off by the force of the airbag detonation. His hand was in the wrong place at the wrong time, firmly planted on the horn when the airbag burst through.
However, other anecdotal evidence has also indicated that the safety devices aren't safe for thumbs, and some driver's ed courses warn new motorists against gripping steering wheels with their hands in the classic 10 o'clock and 2 o'clock positions for fear of losing their fifth digits in a wreck.
The MythBusters blew up the latter theory by creating a crash-test dummy with lifelike arms and hands (and, of course, thumbs) and subjecting it to a series of airbag explosions. No matter what position the dummy's thumbs were in on the steering wheel - curled around it or resting on top of the wheel - the airbag consistently struck the dummy's arms first. Consequently, the inflating bag forced the arms outward, bringing the hands off the steering wheel before it could make contact with the digits.
The MythBusters didn't test the thumb risk associated with laying on the horn like The New York Times' subject did, but their tests did bust the myth that an inflating airbag can blow off your thumbs while they're in the "10 and 2" positions on the steering wheel.
Guess your grip is safe.