Re: Restricting access should be illegal?

Consider the following legal code:

-----------------------
#include <stdio.h>

class A {
   public:
     virtual void Member() { printf("A::Member\n"); }
};

class B : public A {
   private:
     virtual void Member() { printf("B::Member\n"); }
};

int main()
{
     B *b = new B();
// b->Member(); // error, B::Member is private
     A *a = b;
     a->Member(); // calls B::Member
}
-------------------------

Shouldn't restricting access to an overriding virtual function
be an error? After all, we can get at it anyway via an
implicit conversion. Does anyone know of a legitimate design
pattern that does this?