At least a real life cabby has a chance to say no or report the situation. Who will do so with an explosives-ladden self-driving car?
Say no to what? Suit cases in the trunk? What cabbie is going to say no to that? Then of course there’s a million other ways to get a car. Remember the WTC and OKC bombings were done with a rental trucks. If bad guys want a vehicle, they’re gonna get a vehicle. Since half the guys blow themselves up with the bomb they can always use their own, not gonna need it later.