Five people died of carbon monoxide poisoning from a gas heater that had been improperly installed in a cabin by the owner, who had not extended the vent pipe far enough above the roofline. The instruction manual had stated that the pipe needed to be vented outside but did not specify how far outside the pipe needed to extend, other than having a drawing that showed the pipe extending beyond the roofline. The manual also said "Warning: to ensure compliance with local codes, have installed by a gas or utility inspector." Do the victims' estates have a product liability action against the gas heater manufacturer for failure to warn? Why or Why not?