Tradition dies hard in aviation. Piston-engine aircraft have been using rotary magneto switches forever. Since the mags can operate without any airframe electrical system at all, manufacturers incorporated a key lock into the switch as an anti-theft device. Putting the key into the switch meant that the manufacturer didn't have to have some other device to disable the ignition.
In the 1960's, when electric starter solenoids became widespread and you no longer had to pull a cable to manually engage the starter, then a button was often installed on the dash, or a spring-loaded "start" position was incorporated into the mag switch. (Some Piper airplanes had a weird one in which you actually had to push the key in while turning it to the "start" position - kind of like an old Volkswagen for those of you old enough to remember.) Some twin-engine fixed-wings used regular ol' toggle switches for the mags, and buttons (or spring-loaded toggles) for activating the starter. Some singles did too - Aeronca Champs had the toggle switches mounted on a panel on the wing root or in a recessed panel on the sidewall between the front and back seats..
Instead of designing special magneto switches for helicopters, r/w manufacturers simply used existing TSO'd fixed-wing switches. Old helicopters, with no locks on the cabin doors and no key needed for the magnetos were ridiculously easy to steal, if you were so inclined and talented. Until recently, I don't think I ever saw a Bell 47 or Hiller 12 with a key-type mag switch. In the 1970's Enstrom finally built their ships with a key-type mags. Robinson, obviously, followed suit. Enstrom put the starter button on the collective. R-22's had the "start" feature built into the mag switch. Later R-44's had a separate starter button (or two). Ahh, consistency in aviation!
Whether the legend for the mags is printed on a ring that surrounds the switch or on the instrument panel itself, I guarantee you that there is a notch and keyway affair in the switch and panel that keeps the barrel from rotating and being misaligned with the legend.
The most obvious explanation for this R-44 crash is this: Even with the key in the "Off" position, one of the mags was ungrounded. We do not know whether this was due to a faulty P-lead coming off the mag, or a defective mag switch. Bottom Line: he was running on one mag. At some point in the takeoff, the connection between the operational mag and 'ground' solidified again (perhaps through vibration). And since the switch was in the "Off" position, what happened was what was supposed to happen: The engine died.
Apparently, the crash happened at 10:00 a.m. Reportedly, the accident flight was the third flight of that day, which meant the first of the one-hour flights was probably around sunrise. I don't know about any of yous guys, but I sometimes experience a "mid-morning slump" in energy and attention levels when the first cup(s) of coffee wears off.. And, being the third flight of the day, our hero probably overlooked some of his usual first-flight-of-the-day procedures...like a mag check, pre-takeoff check...hover-power check, etc. Complacency kills, right? But come on, we see it a lot. And if we're honest, some of us are probably guilty of it too. Me, I'm not saying either way. All's I'm saying that I understand how this probably happened.