Regarding the relation b/w seat belts and srs!!!
The purpose of seat belt is to hold back the person from going along the inertia of the previous state of the car!!! in short, if the car crashes, the driver is not thrown out of seat at the speed car was traveling and his body comes to rest along with the car. If he dont wear seat belt, he will be traveling at the speed of car (e.g car was travelling 60KM/hr before crash, he will be traveling with the same speed after crash). This will result him hitting the steering.
Now imagine, If you are moving towards steering at 60 Km/hr, and air bag deploys , which has alot of force of deployment. You will be hitting an object that is traveling towards you very quickly, while you are also traveling at 60 Km/hr.
What will be the result? This is lethal and the person may die in this case, His/her neck can break easily.
This is the lesson for the people who by pass the seat belts just to shut off the Seatbelt warning indicator, the risk to their lives is double than the people who do not wear seat belt at all!!!.
MORAL OF THE STORY : PLEASE WEAR SEAT BELTS!!!