Airbags are triggered by a number of sensors at the front, and sides of the vehicle.
I have worked with an airbag producer and they are calibrated EXACTLY for the layout of a vehicle AS IT LEAVES THE FACTORY.
If you add, say, a large chunk of aluminium to the front of the car, it is reasonable to assume that the frontal crash behaviour will be affected, and similarly the airbag deployment characteristics will be changed.
So, yes, the cop definitely has legs to stand on.
Do not assume that you are always (ever!) right, the officer is right in this situation.