Threatening aggressive behaviour with landing and ejection by police doesn't stop that from happening so why would any threat stop someone from taking their bags out during evac.
i think the reality is the "training" doesn't sink in and faced with emergency the shock of the situation doesn't make people think clearly or to reasoning.
The best thing the cabin crew can do is keep the exit clear once the passenger has brought their belongings to the door. So the bag had to go out at that point.
This argument will roll and roll like the enormous "hand luggage" but unless your faced with the emergency yourself you won't know what you'd do.
It's hard enough getting people to board the aircraft. The amount of times I've been sat at the front of the plane watching people board. Stop at row 1. then look at their ticket. Read it out loud. 27f. Then say something like is that at the back of the plane looking at row 4 thinking it's somewhere near there....
its no wonder the elements of the safety briefing fall on deaf ears.