The hardware will be standard, but almost certainly you'll pay extra to enable it. (If they do it the same as similar features in the past, there will be a discount to enable it at order, or you can do it later at a slight premium.)
That'll be an interesting court case: the first time a fatality is the result of unactivated safety features on a car that's fully capable of preventing a collision.
Tesla has already said that the Model 3's safety features will come standard, though it wouldn't preclude such a lawsuit against the owner if the features weren't activated.
