Aside from just the potential for accidents, one has to consider the potential for irrational actors or those who choose to employ game theory more recklessly. And when I think of Metcalfe's law, I feel this sort of horror about the idea of proliferation and the loss of control in communication (which was of course vital in preventing Armageddon during the Cold War.)
I think ultimately, future security will come from defensive technology and I believe that's the most noble pursuit for engineers wishing to leave an indelible mark on humanity.
There is of course no defensive solution against those who wish to build Sundial [0] or Poseidon [1]. Humanity appears to be unequipped to carry the mantle of life.
[0] https://en.wikipedia.org/wiki/Sundial_(weapon) [1] https://en.wikipedia.org/wiki/Poseidon_(unmanned_underwater_...