"...What happens in specific, rare conditions where GA mode is not initiated even though selected ... Someone has overlooked the point; a hole in the logic or the text, a latent factor, a hole in the Swiss Cheese."
What happens is that pilots with reasonable survival instinct would become proactive and intervene MANUALLY by pulling back the stick/yoke/wheel and shoving and holding the throttles/thrust levers forward. At most Airlines there is a statement on page 1 of any operating manual which says that: Trained procedures, manuals and SOPs cannot cover every conceivable operating snafu, and that pilots are not constraint from exercising common sense. No?