There are literally thousands of products in use today that are not being utilized per the intended design. Kleenex was originally intended and marketed as a cold cream remover not to blow your nose. WD-40 was a water displacer and corrosion inhibitor. Rogain was for high blood pressure. Play-Doh was wallpaper cleaner.
If we always followed the rules and never deviated from intended uses of a product would we even have the RV's we have today? Someone many years ago took a truck chassis and built a house on it and that has matured into what we enjoy today. The chassis manufacture never intended this use. I suspect the first AC in a coach was when someone pulled a window unit from their home and hit the road.
Granted breaking the Law of Unintended Consequences can resulting in rather severe penalties but unless we try, unless we live on the edge how will we ever know. By human nature we will always try to do new things with old stuff to see what happens and with this application for many of us the results have been excellent. Necessity is the Mother of Invention.
Following postings here, on IRV2, boaters forums and such concerning this use of product not as intended I think there are much more with positive results than problems but then I may be biases considering my success.