The case that I make is that few of us would ever note that a very forward CG could cause roll instability for a variety of reasons. First, few us would intentionally balance a plane that degree of nose heavy. Mine happened because of a procedural error when balancing. Added to that, is that additional dynamics might be needed such as a low wing plane with a top heavy mass. All any of us can say, is that we experienced it or haven't... and just because someone hasn't experienced it, doesn't mean that others haven't.