Now, someone will have to check me on this, but I believe that airliner cabin pressures are equivalent to a 10,000 foot altitude. Again, that's a fuzzy memory, so someone will have to check my figures.
Now, a change from sea level to 10,000 feet is enough to make any pressure container rupture--probably rather violently--which insures that the cabin gets filled with OC. And since the aircraft is a closed enviroment, the OC keeps re-circulating.
Can you imagine trying to land a plane with your eyes slammed shut, and your lungs full of pepper spray? Yarg.
This is about the only 'common-sense' rule that I can think of, just off-hand.
LawDog