Airbags are triggered by acceleration sensors.
Thus the fitting of an aftermarket bumper does not cause them not to work.
The issue is that, if your bul-bar is significantly stronger than the factory bumper, you lose the "crumple zones". What happens then is that, should you hit something, the car de-celerates significantly faster than a standard one.
The result of this is that the airbags may trigger much more easily (or could I say in a much smaller accident) than they normally would.
As a result, the repair cost of a miner fender-bender might significantly increase due to the cost of replacing the airbags.
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