Ok, I know we try not to complain too much about the science on this show; but the RTG just bugged me. 1) radioisotope thermoelectric generators are fairly low power devices. The three on Cassini put out about 700 combined watts. That is less than a single 15 amp circuit for your house. The smart home can't possibly be run off that little power. 2) You don't need to access the thermocouples and the plutonium to turn off power to the house. Just disconnect or cut the power lines leading from the generator to the rest of the house. 3) Even if you did pull the thermocouple, it is unlikely to release any plutonium dust, and lump plutonium that is just undergoing natural decay (rather than being in a reactor) isn't likely to be lethal. Certainly not from short (less than a day) exposure.