We already have no shortage of machines powerful enough to turn on us. A steel rake lying hidden in the grass for example. Everyone knows the apparent danger with these things, yet this tool has managed to infect our very ethos to the point where its potentially operator-harming design has remained unchallenged for 100 years, perhaps longer. I trust there will still be people getting smacked in the face with rakes in 100 and 1000 years from now at this rate.