I haven’t checked the validity of your statement, but I’d guess this is because airbags are calibrated to go off with the assumption that the occupant is wearing a seatbelt. Airbags should only activate if a collision is hard enough that a person wearing a seatbelt is likely to impact the inside of the car. Without a seatbelt you will not only injure yourself bouncing around the car on a much lower collision speed, but also likely not be in a position the airbag expects you to be when it activates.
This is not my field, so this information comes from articles I’ve read over the years: when they first introduced this functionality, it was explained plainly as: your kinetic energy + the kinetic energy of the expanding airbag > your kinetic energy + negative energy absorbed by the deflating airbag.
Nowadays I gather that things are more complicated, but still, the status of your seatbelt is part of the data your car uses to choose a protection strategy for you. Fooling it with devices like this goes against your own interest twice.
I haven’t checked the validity of your statement, but I’d guess this is because airbags are calibrated to go off with the assumption that the occupant is wearing a seatbelt. Airbags should only activate if a collision is hard enough that a person wearing a seatbelt is likely to impact the inside of the car. Without a seatbelt you will not only injure yourself bouncing around the car on a much lower collision speed, but also likely not be in a position the airbag expects you to be when it activates.
This is not my field, so this information comes from articles I’ve read over the years: when they first introduced this functionality, it was explained plainly as: your kinetic energy + the kinetic energy of the expanding airbag > your kinetic energy + negative energy absorbed by the deflating airbag.
Nowadays I gather that things are more complicated, but still, the status of your seatbelt is part of the data your car uses to choose a protection strategy for you. Fooling it with devices like this goes against your own interest twice.