Required Neutral for HS220 smart dimming switch?

If a switch box does not have the power feed going through it then it doesn't have a neutral.  If it functions as a switch to some light fixture then it is just interupting another power source before that power can travel through the light fixture and back to neutral.  If such a switch box is grounded through the grounding conductor, and since the ground and neutral terminate at the same location in the breaker panel, Why not just connect the HS220 smart switch neutral to the ground wire and the load and line to the hot and return wires.  

Or, can/should a separate neutral wire be run from any close by neutral to the switch box to allow a HS220 connection.