Why is the PCV valve grounded?
Under ideal conditions they can freeze during operation. More importantly it keeps condensation from settling in the PVC. The resulting pool of water would freeze.
The condensation remaining in the valve above the freezing point would cause the valve to fail prematurely due to 'rusting/corrosion/failing spring' of the one-way valve mechanism.
God only knows why GM thinks the PCV valve would freeze ever up. Maybe just worried about condensation freezing somehow in it.

