At the risk of being thrown off the forum, especially considering the loss of loved ones to posters in this thread, I humbly offer the following:
Seatbelts are a wonderful idea, and so are airbags. I wear my seatbelt absolutely every time I get in the car. My sub-2-year-old rides in an approved child seat without exception.
That being said, life has risk, and that will never be eliminated, no matter how many rules, laws, regulations, societal peer pressure, etc. we come up with.
There is a whole continuum of things that can be regulated - at the obvious end are things like intentional harm of other people - murder, theft, etc. At the other extreme are hypothetical regulations such as needing to get permission from the government to take a trip in your car at all - simply being on the road increases your risk of death or injury in an auto accident (duh), therefore we better make sure that no one goes anywhere unless the trip is important enough to justify the risk.
Where is the appropriate place to draw the line? In the US we're seriously considering regulating fast food, and even here on the FOG there's speculation that the Carvex delay is related to a perceived safety issue with the strobe light (which Festool has never corroborated - I'm not sure where this theory came from exactly). We have outlawed incandescent lightbulbs (and replaced them with toxic CF bulbs that in my experience don't last any longer than a conventional bulb did).
In the case of seatbelts the cost benefit analysis seems pretty clear that grave injury can be saved by doing something not terribly onerous. I'm less sold on the ever increasing age and weight "suggestions" of child seats, since those can be a lot more intrusive, and can have some unintended consequences - parents reaching back to give their kid something to get them to shut up, etc. I know my kid has been a lot more pleasant to ride with since we turned his seat around.
I believe that some regulation of products is a good thing - I'm glad my car has airbags, and it wouldn't without the government mandating them. I am concerned about the trend towards the "nanny state" where the government tries to do all the thinking for us and our cars get chips put in them that won't allow them to exceed the posted speed limit, or I can't put up a piece of sheetrock in my house without being "licensed". I'd like to be able to live the highest possible percentage of my life without having Big Brother looking over my shoulder, choosing which risks to take on my own, and suffering the consequences, good or bad.
I concede there's a lot of gray area here, I'd just prefer to err to the side of "suggestions", rather than laws.