I disagree. The rule states that the tiller extension is to be non-conductive, not just that the outer surface is to be non-conductive. If instead of carbon fiber, the stick was made of a copper rod coated with a thin heat shrink, would you still have the same opinion?
Just for kicks... (and it's winter)
The rules don't clearly define how to measure "non-conductive". Which is part of the problem. Therefore depending on your desire to have a carbon extension or not, it will be very arguable. It could be said that the rules state that the tiller extension is to be non-conductive, therefore if I encase a copper rod in plastic, then yes, it is now for all practical purposes "non-conductive".
But the copper rod is going to be much heavier that carbon fiber and therefore won't sell very well.
I'll tell you that I could sail with a gold tiller extension and not have any concerns with being electrocuted.
The mast, and many of the components you sit directly on while sailing are made of aluminum. Aluminum is more conductive than copper. Go sailing in an electrical storm and you're more likely to have fire bolts shoot up your arse, than to get your thumb blown off.
Seriously, you"re sitting on an aluminum crossbar, holding onto a stainless steel cable attached to a 33 ft. aluminum lighting rod.
And we're discussing the conductivity of a tiller extension?
The safety issue, and the cost issue both appear to be just a couple of red herrings.
In my opinion, the current verbiage appears to be a holdover from the past with no current bearing on performance to support its continued use.