well, for some cars even if you turn it off, it will automatically turn on after you restart the car. it wont stay off. so you need to off it everytime you drive. surely sometimes you forgot or fedup and never bother to turn it off

the problem is the buyer for the car in this incident never bought the car for that system, he mentioned that he never use adaptive cruise control even once. he prefers to drive it himself.
he also tried a few times to turn off the CMBS but it continues to turn on after you restart the car, so he simply didnt do it anymore.

must be fed-up if you have to manually remember to turn off the CMBS each time you start your car.

what makes it worst is that he actually is alert , and did continue to press the accelerator but the car seems cut off and does not respond to his action.