Rod,
I think (and I may well be wrong) that metal acts as a conductor and carbon fibre acts as a capacitor - so carbon fibre is more likely to overheat and blow when a large discharge takes place across it than metal which shields the contents and passes the charge on to another point. The entry and exit points in the glider wreck mentioned previously were the aileron push/pull as far as I remember and the wings just vapourised leaving the metal bits behind - a perfect time to reach for the Cirrus parachute handle.
Any materials scientists out there?
I'm sure Stephen Hawking could help with this one.
Alternatively we could go to Top Gear again - perhaps Jeremy Clarkson (as Hammond is out of action for now but hopefully making a speedy recovery) might volunteer to sit in a Sinclair C5 (composite car) and repeat the Hammond lightning experiment - it certainly might improve his hairstyle!
Actually a reliant Robin (another plastic car) would be a fairer choice as it is not a convertible and would not expose the Clarkson perm to the megawattage so directly.
SB