you don't want your car to refuse to move when you are stuck on a railroad crossing despite the gate in front of the car being down. there must always be a way to override the autopilot.
Moving off a railroad track at what maybe 15mph max is very different than doing 70mph down a cut de sac double the posted speed limit. I am not saying FSD should prevent any forward movement, how fast can it go in reverse? Probably something like that.
yes, but according to the car you'd be crashing right into a barrier no matter the speed. the car needs to ignore that and allow you to break the barrier.