You don't need proof IMHO. When lightning actually strikes something the effects are rather dramatic.
This is why you need to PHYSICALLY UNPLUG sensitive electronics. That or have a master disconnect switch on the NEUTRAL entrance feeder to your home or rig. A strike on nearby earth can travel to grounded electronics and jump to neutral and find a path through the circuitry. Extremely high voltage has a mind of it's own.
Want an example?
Auto ignition coil. You don't need to touch coil negative (ground) to get a jolt. Now magnify that voltage by a factor of 100. Scary
