You can be serious....
What can be learned from this accident is how serious the consequence of panic. Aviators have to learn to be calm in the face of distraction and danger. We are trained to cope with in an orderly fashion the lightning strike, the hornets in the cockpit, the hail, the microburst and sudden loss of oil pressure in the starboard engine.
And then we invite the unwashed public to climb blithely into the rear of the aircraft, and ask them to follow our rules. No guns, no knives, no crocodiles. Please fasten your seatbelt and remain seated until the captain has turned off the sign. It is asking a lot of travelers not to panic when badly frightened, whatever the cause. This is where cabin crew prove so important. Tea, coffee and blankets, that's just window dressing for the real job, which is keeping the pax informed, reassured, and well behaved.
The consequence of a sudden rush to one end or the other of a C of G sensitive aircraft is clearly something that must now be addressed in advance, the cabin crew (or pilots if no cabin crew available) must make it clear to all on board in no uncertain terms.