Hello!
Are these urban legends or do the inspectors actually keep digging until they come up with something? I would like to think they are reasonable but have no idea.
They always try hard to find something... Never heard about that oxygen thing through (under EU-OPS there is no requirement to use oxygen masks anyway).
I fly on 150 to 180 days every year and get a SAFA inspection maybe once per year. Don't argue or discuss with them - it's useless. It is best to wait until you get a copy of the inspection report a few weeks later through your aviation authority and then comment on all the findings. Usually most of them will go away that way.
Last time they complained about a bare-metal transponder antenna on the belly of our aircraft: "this will corrode quickly and stop working" the inspector told me. I took a close-up photo of the antenna (including the "do not paint" label) and attached it to my comments of the report.
Happy landings
Max