Yep - the best protection is to have and TEST a fuel cutoff valve.  No fuel = no fire, and fiberglass doesn't burn well on it's own.

That all depends on the resin used. Most Fiberglass uses a polyester resin. It takes a little effort to get it started, but once ignited it burnes quite well. I have see nothing more than hot brake lining fragments ignite the polyester fiberglass nacelle of a wind turbine in White Deer, TX. With no other fuel involved, 99.9% of the nacelle burned away.

 

Fiberglass yachts burn as good as any bonfire. Fiberglass fires are the source of about 20% of my income these days.

Rob