turning my system on during lightning storms

Direct lightning creates plasma about 1 foot in diameter and there is no wire in the world to bring it to ground, but if it gets one of the smaller "branches" it might protect as long as wire is thick and does not have sharp angles (short time = high frequency). I have tall street lamps around my house working as grounding rods. Not grounded antena migh appear taller than street lights (or trees).

Kijanki, your comment about the plasma ball reminds me of a time I was driving in Tennessee during a thunder storm. I was approaching a corner and witnessed a lightning bolt strike a tree. It was probably 40 yards ahead of me. What I saw was a big orange ball engulf the base of the tree when the lightning struck. It was a truly awesome sight.

Timhru - I experienced horrible thunderstorm in the mountains when I was young. I remember people closing windows and talking about plasma/fire ball that can move horizontally and come thru the window - scary.

I assume everything needs to be unplugged? Let's say that you unplug everything except the tuner. Will lighting find its way through the interconnects and fry everything else?

Current will find all possible paths to ground even if your tuner provides easy one. When the rest of equipment is unplugged and well isolated from the ground current won't flow thru it but will flow thru center wire of your interconnect to input of an amp and back (high voltage will destroy/short input) thru interconnects ground to tuner and earth ground. This is not very "efficient path" but your amp's input doesn't need much to get damaged. Unplug everything.