Except for through-hull fittings, it's pretty tough not to at least inadvertently ground the mast and associated hardware due to all of the wiring in the mast. I agree with doing what ever makes you happy because I don't think anything is going to save a boat from being extraordinarily damaged from a direct lightening strike.
But what about the crew? I thought grounding the rigging to the engine block was pretty standard, but was suprised to learn my Catalina 36 was not wired that way at the factory.
The explanation given was that they feared it would give a false sense of security and that due to their nature grounding systems were difficult to inspect for long term maintenance. The manual suggested sailing where lightning was not a threat. Ok, great, I'll just sail my 36' boat indoors!!!! WTF.
The owners manual also contained the then current standards for grounding systems, if an owner wanted to install a system, but I'm perplexed for the very reasons raised here. Grounding would seem to make you a more likely target and the damage is likely to be pretty bad either way so whats an owner to do?
The real question for me is are the occupants of the boat safer if its grounded or not grounded. Sailing where lightning is not a threat is not a good answer for me. Thunderstorms can pop up all through the sailing season on the Chesapeake.
Any good evidence that the crew is safer one way or the other?