It's the insurance lobby. They want you to pay in but, they don't want to pay out. Hurts their bottom lines.
Air bags was pushed by insurance companies. I believe just about everything having to do with driving restrictions is directly related to an insurance company.
I think you are on to something.......Sherlock.....Holmes that is........(humor)
Actually, airbags were pushed by Elizabeth Dole and the DoT more than the insurance companies. See http://www.fee.org/vnews.php?nid=5192 Mandatory seatbelt laws came as a result of Dole's blackmail against the automakers, threatening them with an airbag mandate unless seatbelt laws were enacted.
Poor suckers, they thought they could trust a government bureaucrat, but wound up screwed with the airbag mandate anyway.
Insurance companies' costs are massively increased by airbags - they are required by law to be original equipment, and a single fender bender with no injuries can rack up thousands of dollars in airbag repair costs alone. See http://www.lemurzone.com/airbag/cost.htm for an example scenario calculating nearly $4,000 to repair the airbag system on a 1994 Taurus.
What's the result? Poor people can no longer afford cars.