content: False equivalent: the roller coaster has been created with the physics of free-fall in mind. It was designed with zero operator operations except upkeep and maintenance. A roller coaster is no better then a fancy building that puts its designer possibly more at fault if something goes wrong. The car however, can move in every planar direction, accelerate and de-accelerate, which the diver controls interactively with environmental stimuli. I'm not saying making a robot do the work is a bad idea, but an inanimate object can't be held at fault when there is a human present that can stop its wrong or illegal operation.  For example, a CNC machine is suppose to be overseen by an operator because mistakes do happen, and the machine may not be able to identify and correct a mistake.  Rare possibility, but there could be an event a robot can't catch or correct for, but the human can.