Because iFixit are UNSUBSTANTIATED and UNSUBSTANTIATED, and I want to be just like them. Wink. Nudge. Just kidding.
Standby output of Apple's MagSafe Power Adapters varies between models. Yes it is often said to be "6V", but that is "old knowledge" which pre-dates 45W and MagSafe 2 models. (I'll share two standby potentials which I measure: Model A1424 is around 3,15 V; Model A1435 is around 0,6 V.) I hope this little bit of knowledge will be useful to anyone, whom suspects their unit is faulty just because its output potential is not 6 volt.