This is an interesting issue. Certain electronic equipment actually feeds some current back on the ground pin. Computer power supplies and other electronic equipment often contain capacitors from each AC prong to case ground to meet the FCC requirement for conducted radiation. If the ground connection is broken, the resulting capacitor voltage divider can cause the case to float at half line voltage. The current is low, but it can give a surprising shock when not expected.
While connecting the switch neutral to ground certainly violates the code, and is not recommended, the current involved is not that much higher than from the capacitors described above. The problem arises when there is any break in the ground return back to the electrical distribution panel. Should that happen, the screws and a metal switchplate would float at full line voltage. Even though the current is still fairly low, it is high enough to produce very serious results if the unfortunate individual has low enough skin resistance, and manages to touch a grounded metal object at the same time.
Electrical shocks are nothing to mess with. I speak from experience.
Jeff