Any wire can have its current modulated, i.e. an induced signal. The longer the wire, the more likely it is to be affected by modulation. And any wire running parallel to another wire that has modulated current will itself pick up a modulated current (= signal).

To sum up: keep your grounding wire as short as possible and keep it well away from other wires. Also for safety sake you should connect a resistor between you and the grounding wire; I'd suggest at least 470 kilo-ohms.

(I have a degree in electronic engineering.)