I have dropped a chain over the side that was attached to a side shroud while I was sailing on my old boat (deck stepped and encapsulated keel). I''m still here, even a few times when in the middle of a storm. I think its just luck....
But forget about attracting or not. I think the REAL good reason for grounding is not about attraction or less attraction, but rather, when it hits the odds are "MUCH" more in your favor of not getting a person on board bZAPPED if you boat/mast is grounded.....THAT is the reason for it IMHO.