It will have a effect on the backside as well. The amount of effect to the backside is not completely clear.

I seriously doubt if turning off appliances and electronics will have much of an effect because the power cord and antenna, if longer than 10" will pick up enough energy to burn out the interior circuitry. Disconnecting the antenna and power cord, at the unit would help but then the question remains as to whether there is sufficient wiring inside to pickup enough voltage to still fry everything inside.

In 1859, railroad ties & telegraph poles were set on fire and the telegraph poles had glass insulators between the wires and the wooden poles. Also, there weren't any grounding straps running down the poles or from the RR Rails.

The effects on today's infrastructure and equipment is still largely unknown despite 30+ years of testing and research.