I have done alot of mods to my OFF-ROAD POPUP RV Trailer. Most have been electrical in nature. I have also modified alot of wood work inside my RV trailer.. I also have some similar type mods to my house as needed.
All of these mods for the most part was not inspected by any authorities for code or safety inspections.
Like said above if any of these mods ever cause deaths or other large discrepancies then the insurance companies probably would have big implications on settlements...
It's a big catch 22 that all of us do...
With all of this in mind I try to follow code with everything that I do...
There of course are some things that it would be very important to get properly certified by a licensed technician...
Roy Ken