The car would likely sense the issue and alert you that the system is offline assuming that you did not intentionally do that to your own vehicle. Also, I believe that a lot of the vehicles use a camera as part of the collision system or at least Toyota’s. Edit: don’t quote me on the camera thing though
I have those features in the car i drive now. They can be disabled with a single button.
The lane keep assist actually has to be manually enabled every single time the car is started.
I do however understand the broader point you are making.
The car would likely sense the issue and alert you that the system is offline assuming that you did not intentionally do that to your own vehicle. Also, I believe that a lot of the vehicles use a camera as part of the collision system or at least Toyota’s. Edit: don’t quote me on the camera thing though