Is it 2 stage or 3 stage? I can't remember.
Originally Posted by Steve83
The other possibility is that, if you're NOT belted, and the bag goes full-blast, it could do more damage to you than the dash would have.
True. Though if you're going slow enough that you're only going to hit the dash, I wouldn't think it would deploy. It's when you're going fast enough to go through a windshield that it would deploy, and I'd think with more force if you're unbuckled.
If you crash at 50, truck goes from 50 to 0, but you keep on going at 50. Less force is required to stop a moving body that is going 20 (slowed down by belt), as opposed to 50 (without seat belt).
If you're only going 20, and you're with seat belt, it might not go off. If you're without seat belt, it might go off with half force, or maybe nothing at all, thinking a deployment might do more harm than, say, the dash (like you said.)
Who knows. Either way, I wear my seat belt, so I don't worry too much about it.