I certainly understand the concern about back feeding. At the same time, it just adds more costs to construction and its another attempt to "idiot proof" an electrical systems from idiots. It should be a loco enforcement, not a code issue. It is not the premiss of the code. If installed correctly and used correctly, there should be no issue. It's not a design manual. Just the minimal safety requirements. I may be delusional by I still believe in that, even after the AFCI debacle...
