Insurance fraud is not an accident, it is a crime. Big difference.
Also, I should have mentioned rear-end accidents caused by the lead vehicle 'stopping short'. That is always the fault of the following vehicle for not leaving enough space. There are cases where the lead car may be at fault, such as merging in too close to following cars, but that is different from just stopping short, which is what was originally discussed (brake assist causes car to stop quicker than following car without assist).
Also, there is a big difference between fault for an accident and compensation for an accident. In the insurance fraud case, the following vehicle is still 'at fault', but the leading vehicle may be denied compensation if fraud is suspected.
I didn't find any references to 'overbraking' being against the law, while following too close clearly is.