Thanks again for the info.
I noticed today in the Airbus FCTM that leaving the SEL light on is considered an "identified risk" so I guess that provides a little insight too.
Another question I have by way of a survey I guess, do most carriers require the pilot to wear the oxy mask when the other pilot leaves the cockpit?
My old (bankrupt)carrier long ago did but then dropped this procedure when AI provided feedback that it was not required with quick donning masks.