As to if a position exists where you cannot keep ma ai the it's obvious it would then depend on your ability to enter well wouldn't it?
I would think so. Happy to see you agree.
I raised the point in the first place because you seemed to claim that "keep ma ai" was a sufficient response for most (if not all) situations, and indeed that doing so is the central insight of aikido. I apologize if I have misinterpreted your position.