ev0lution

Hypoxia isn't friendly like that. You don't feel like you're losing oxygen, you will just fall unconscious.

Pilots are trained to 'detect' hypoxia but it is still /incredibly/ difficult.

>Even if there was a slow decompression to 13,500 ft cabin altitude, almost no one would be unconscious.

This person's theory claims that the autopilot would /maintain/ the aircraft's altitude. The cabin may slowly depressurise, but the altitude remains the same. TUC at 35,000 feet - normal cruise altitude - is only 30 to 60 seconds (on average!), which is nowhere near the 30 minute mark that it would be at <15,000 feet.

I am not experienced enough to comment on the plausibility of other aspects of this person's theory, but in terms of unconsciousness caused by decompression, it definitely seems plausible.

I'm not sure about the sensitivity of pressure sensors so I can't comment on that, but in most cases where oxygen masks are required, it is rapid decompression caused by the pressurisation system failing or a physically broken part of the aircraft that has exposed the cabin to the outside atmosphere. I'm not aware of a case like this (if this person's theory is at all plausible) where depressurisation happens slowly.