Well I've seen some bars fail, and not knock offs.
On the basis of what I have seen, always do up your brake and gear clamps so that in the event of a crash they still will move round the bars rather than break off, because both broken bars I have seen have been where the brake clamp is attached . Blame is surely on them being too tight for the thin carbon at that point, keeping in mind that the stem attachment point is nearly always reinforced, and roughened so that torque doesn't need to be too tight.
IMO, attention to assembly is far more important than the brand or otherwise of the bars.