Just search for faulty airbags and Mazda3 (it's quite a few months back).

The gist of the argument is: front airbags only go off in a full frontal collision wherein the car hits a wall directly. In 90% of accidents, where you hit another car at an offset, hit a post, hit a car or wall at an angle (the majority of accidents are like this, as you usually try to avoid the wall), frontal airbags will not activate.

Furthermore, frontal airbags are supplementary, thus, they alone will not protect you from injury. They may also cause suffocation or broken necks in shorter passengers. Our current passenger side airbags are now being phased out in the US in favor of airbags that do not go off if a passenger is small, short or light.

There used to be an issue, actually, of airbags being able to break the necks of seatbelted passengers because they were made strong enough to catch un-seatbelted passengers. I believe this has been corrected already, though.

Thus, the most important thing is that a car's seatbelts are effective and that the crumple zones work.