A: I have not investigated nor studied the role of electric v. mechanical braking in a Tesla, but there could be related technical issues there as to how much braking is available from the pedal, and how quickly. Logged parameters such as whether or not the pedal is applied (brake switch signal), the brake fluid pressure, longitudinal and lateral accelerometers, yaw sensor, steering angle, and wheel rotational speeds over time can shed light on the unfolding of an incident.
As you said, you clearly haven't studied braking in a Tesla at all. That discussion is entirely appropriate to the blended brakes most of the EV market uses.
Tesla has continuously refused to contemplate blended brakes, largely due to pedal feel/response as I understand it.
Thus, with iBooster, Tesla has the most direct brake response possible - the pedal is pushing directly on the master cylinder piston just like an unpowered hydraulic brake system, and the iBooster adds braking force when the car feels it is appropriate.
Electric braking happens solely by the release of the accelerator.