The reason the device has a polarized plug is, a lot of new electronics uses AC to provide sufficient power to the device. The voltage is then, stepped down and rectified to DC. This is done to protect the equipment. Nuetrals, with a load, can certainly give you a shock. If you have Receptacles that are the older type with no ground, and not polarized, I suggest that you have them changed to GFCI Receptacles. This will protect you and your family, as well as allow you to plug your device in using correct polarity.