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 stated that the pipe had to be vented outside, but did not specify how far outside the vent pipe should extend, other than having a drawing that showed it 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 decedents' estates have a product liability action for failure to warn? Why or why not?