I understand completely. Its not like typical building codes like : Current overload protection (breaker box) that prevents your house from catching fire then could cause your neighbors home to ignite. Safe rooms have no effect on the neighborhood as a whole unlike other safety codes. So yea it would be tuff to sell such a building code.
Ill tell you what though. If i lived in the plains I would for sure have a Safe Room or Shelter regardless of local codes.