It might be worth adding here that under FAR Part 135, no restraint OF ANY KIND was required of the FlyNYON pax. Remember, restraints (seat belts) are only required for takeoff and landing. It is perfectly permissible for passengers to unbuckle and indeed walk around the cabin, even on airline flights! And evidently the AS350 has no prohibition against open-door ops.
So FlyNYON probably thought they were going above and beyond the FAA's requirements by providing the additional harness to keep the pax from falling/jumping out in flight. Ultimately this turned out to be a huge mistake.
I can understand the pilots' resistance. Every idiot helicopter pilot knows that when a helicopter goes in the water it inevitably "turns turtle" as all of the weight is up top. Every idiot helicopter pilot knows that helicopters often burn after they crash (especially Astars). Oh, so let's tether the pax in with screw-type carabiners with attach points that are BEHIND them! Great idea!
Too bad the pilots weren't more forceful in their objections. I'm sure some of them probably saw this coming. Too bad FlyNYON's management wasn't more experienced in flight ops. For they *should* have seen this coming.