Earlier quoted context omitted.
> The driver behind a vehicle is primarily responsible for any rear end collision (US-specific, YMMV elsewhere). Not if you slam on the brakes without cause on the highway.
Here is the general state statute you're up against (as the person rear ending someone on the interstate): “Any person driving a vehicle on a highway shall drive the same at a careful and prudent speed not greater than nor less than is reasonable and proper, having due regard to the traffic, surface and width of the highway and any other conditions then existing, and no person shall drive any vehicle upon a highway a…
That's a bit of a sideshow. Tesla needs to worry about the civil liability involved in making a car that stops suddenly in the middle of the road. For example, "The driver is still 100% responsible, just as they would be for cruise control" is absolutely not going to impress anyone as a defense if there is enough property damage or personal injury involving such a feature to justify a class action.