Gelman amnesia and all that… Even more nitpicky: it’s not a GFCI because GFCI does not detect current leakage between pins that shouldn’t carry current. It me

Gelman amnesia and all that… Even more nitpicky: it’s not a GFCI because GFCI does not detect current leakage between pins that shouldn’t carry current. It measures current imbalance between pins that should be carrying current. The distinction is that a real GFCI (which this USB port is not) does not care whether the imbalance is returning through a third conductor on the power cord or some other path. If this were a real GFCI, it would be able to detect when current flows out through the case, to your hand, though your body and then back though the puddle of watch you’re standing in. That’s not what this is doing. It is measuring unexpected current between the pins within the port for the purpose of avoiding galvanic corrosion (the hint is in the daemon name reported by macrumors).