It's important to know where the sensors are, especially if using say a big hammer to re-arrange the metalwork around the front wheel arches for increasing any clearance.
Is it true that certain conditions have to be met before airbags are deployed, like ignition on, minimum speed etc?
In some cars, eg some skodas, the sensors are in the doors, and even removing speakers, can affect the deployment, as would adding extra ventilation, or driving the car without the door cards on.
So it is important to understand when making mods what affect you might have on these sensors.
I would expect 4x4 vehicles to have toigher sensors, as you wouldn't want the air bags to deploy on rough roads or in off road conditions.