I agree with your original example ("good reason => OK", "bad reason => BAD"). But for the in-between we should default to "not OK" as well, since stopping on a highway is just dangerous.
But damn, I really have little sympathy for all the inattentive drivers not being able to stop in time for the pileup (and hope damages have to be payed accordingly). Maybe, Tesla FSD does not make the streets more dangerous than they already are, after all.