If it can be proven. 25 years ago a scam was where someone would suddenly change lanes to be rear ended like that, then claim "back pain" and sue for a lot of $$$. I don't know how common it was, but when there are not witnesses the courts tend to side with the person being rear ended.

And this is why you should have a dashcam in your car.

Often there were two cars in that scam. One to first follow really close so you are both distracted and reluctant to stop hard.