You don't know a basic which does appear on the ECAM and you adventure to say "not to forget on the next landing". This a straightforward question and your answer is just absurd. Just don't get the point of answering to say that, for real.

There's no sop for that though ALL WHITES OFF next flight will clear everything that was left, so there it is.

My best take: CREW OXY = OFF is the grain source of truth here.

but many marbles and glasses had been broken, lost, or left unpolished along the way.

Now, as the OP themselves would put it, OXY is below the GPWS switches, as opposed to in-line where LDG FLAP 3 is placed.
At the same time quoting verbatim again, the OXY illuminates white when de-pressed to OFF, whereas LDG FLAP 3 shows ON.

https://cimg2.ibsrv.net/gimg/pprune....8b69707ba7.png


EDIT: Upon a second read I understand that "under GPWS sw" in proper English means "within" and I failed to appreciate that.

Either way, it is foolish. Also, I don't press buttons by reading an "SOP Checklist", and I haven't seen anyone trained to do so. Except for one specific case with 'Securing the ACFT C/L' which many like to use in a read-and-do style (result only a little out of sequence) - the one with OXY = OFF - just saying.