One difference with AI is that it is theoretically capable of analyzing your failsafes and overrides (and their associated hidden flaws) more thoroughly than you. Manual, physical overrides aren't yet amenable to rigorous, formal analysis, but software is. If we employ a logic to prove constraints on the AI's behavior, the AI shouldn't be able to violate its constraints without basically exploiting an inconsistency in the logic, which seems far less likely than the case where, e.g., it finds a bug in the overrides or tricks the humans into sabotaging them.