I have a 912S.
As I understand it the throttle was arranged thus so that in the event of cable failure the engine would run, (and presumably could be controlled the old way, on the mag switches.) The probability of cable failure was considered higher than that of spring failure.
On my aircraft I, like most owners of our type, have reversed the throttle connection. While I have had three throttle springs go in autos, I have only had one cable go, and those cables were never inspected. (The inner rusted through.)
Most 912Ss have a clutch to preserve the engine against drive train shock, and inertial forces (Though mine doesn't, it was made in a short window when they were not installed.) Luckily Jemima is a pusher and the prop is well away from the ground, though one of our number struck his prop on his pylon this week. Apparently there is up to 4" tip displacement under certain circumstances!