interesting article. Yes , aware of the complaints about sanitary issue. We were given wipes to clean the mask, first flight. Many did not like. I was a Captain and I expected compliance so I know that FO's had the mask on at least until I left the cockpit. Also even non-compliance forces a mental review by most? I am not going to wear the mask but lets see.... there it is, if i need it... then put it on, Altitude- spin down, FLCH, throttles close, speed brakes, turn, talk.
As for oxygen poisoning. Interesting, who knew. I had several years of military tactical jet flying. we had a rule, 100% O2 required from takeoff to landing. This one did get violated a little. Biggest issue was that on a long flight you used a lot of LOX, liquid oxygen. Not every base could recharge it, if there was lightning in the area they wouldn't. So, there was some mask dangling flying at medium altitudes that would give a cabin pressure around 10k, checking fingernail bed color, monitoring cabin altitude gage often. Also, 100% oxygen dries you out. But oxygen poisoning? We knew about hyperventilation and that risk is higher when using 100% oxygen. perhaps this is the poisoning?