You don't have to disable it to beat the safety system.
They were all pretty much due to inattentiveness, though. Many were drunk drivers.
Many do use defeat devices as well, but not all.
This was all brand new when it first came out and we didn't really have proper regulations for it. Things have gotten more restrictive, but people do still find ways around it and there's no fool proof solution to this as humans are smart and will find ways around things.