FF
"You must quote the permission numbers on your flightplan form. No permission, no clearance"
Is that true for VFR FPs? IME nobody even looks at what you put on a VFR FP; the ATC man just addresses it and stuffs it into the system, and nobody really looks at it afterwards.
There is no feedback mechanism.
There is also no en route clearance on a VFR FP. You can get turned back anytime - except perhaps outside CAS (in a civilised country).
Recently I flew past Serbia/Montenegro, through the extensive NATO airspace there. The VFR FP goes in allright; it was only when I did the usual thing (for the "less civilised" parts) and phoned up every ATCU along the route that I discovered there would be a problem with certain routes.