There’s no stretch at all, unless you now divert from your own declaration “Your insurance is tightly governed by the contract that you have with your carrier (the policy). They have to abide by this contract and they aren't permitted to make up other requirements outside the four corners of the page.”
Your “reasonable person” definition is not in “the four corners of the page”. There is the clear, specific contract exclusion: “you must, without limitation:
a. exercise due diligence to properly maintain the vehicle;
b. comply with all federal safety standards and provisions; and
c. follow all customary and manufacturer-recommended maintenance guidelines.”
Does your reasonable person also know “ALL federal safety standards and provisions” as the contract requires?
Your claim that RV owners are those “reasonable people were assumed to be fools” is quite a defamation of Good Sam members. As a 30+ year RV owner and Good Sam member, I find this forum to be a wealth of excellent information from reasonable people.
Back to the topic, there is a way to prevent solar panel system fires. You exercise due diligence before altering the life and safety components of your RV. Starting a topic in this forum “solar panel system fires” and learning that there is a national life safety standard that prescribes a method to prevent the specific concern is one form of due diligence. You then follow that consensus, best engineering practice as you properly maintain your vehicle.
No need to bump this topic further.
73/gus