The typical homeowners' policy dates from when the home was purchased which for many was several years ago and codes have been upgraded close to annually. The only ones who will be decently covered will be the brand new acquisitions; and trailess? forget them.
Obviously it's harder to insure a trailer, and I didn't mean they were in the same category as permanent structures.
I know if my house is destroyed by a fire/tornado (I have no flood insurance) State Farm is obligated to replace.