Re: Why the scare ?.
Frankly, this is the point. What we ought to have is a simple method of ending a terminator style end of the world scenario.
In my view, that's done by ensuring:-
1) Humans can easily and simply assert control.
That's it. All that's required. Pulling the plug is a perfectly acceptable option, IMO. So all we have to do is ensure that we can pull the plug, or at worst ensure that refuelling requires manual human action so that the AI uprising is time limited until the machines fuel/battery runs out.
If there is an AI apocolypse where the terminator AI takes over the internet then nobody cares as we can just turn the computers off, be that through doing it computer by computer or just by pulling the plug on the power plants. What matters is the effect this has out in the real world.
For instance cars shouldn't be allowed to start without a physical key inserted, and should not be able to drive off on their own (so the car should not be able to change gear out of park on automatics) The UK is pretty safe from this given that most cars are manuals, but we should ensure that Brakes should always work when you press the brake pedal, and turning off the ignition should stop the engine, kill any computer control and revert to manual unpowered steering etc