Misrouting the cable is a hazard because the keeper pin can cut the cable very quickly, sometimes in a few minutes of flight, due to the sharp radius it makes for the cable. The fraying is almost immediate, and as wires are cut, the fraying rate increases very quickly.
For the S-76, an astute pilot can sense that the cable is not routed properly, because the yaw forces are higher when the cable is not riding on a smooth pulley. If the cable is misrouted, the moving the pedals will cause the collective to nod up and down, because the extra yaw forces finds an easier path back to the collective through the yaw to collective mixing. While a slight amount of this collective nod is normal, if it gets big, and the TR has recently been maintained, have an inspection done.
The 76 has more than a centering spring, it has a mechanism that allows almost full pedal range with a broken cable. The device centers the TR pitch if both cables are cut. A similar device is on Black Hawk and S-92, as well.