You don't think that e.g. alerting as to a wrong-way driver or that panic braking is starting before the car behind you could detect it from relative motion has

You don't think that e.g. alerting as to a wrong-way driver or that panic braking is starting before the car behind you could detect it from relative motion has any ability to add margin? V2V is being discussed to augment human drivers and prevent them from rear-ending / improve collision mitigation systems. Why can't it help machines too.