In my limited understanding of the chemistry, gained from numerous posted references
online, it is NOT the absence of oxygen that makes stainless fail. That's a half-truth.
Stainless fails from crevice corrosion
when it is kept damp AND deprived of oxygen. That is, submerged in stagnant water
like that sitting in a bilge
, unpumped and unchanged for months on end while sitting in a yard. Or buried under layers of electrical
tape on a swaged fitting, allowing moisture to wick in and then keeping the moisture soaking the parts
Covering the steel while it is dry, in such a way that it is KEPT dry, can do no harm and will provide total protection for stainless. This is analogous to the condition that stainless steel bolts are in, when someone has applied threadlock or other sealants and bolted them up in threaded assemblies. SEALED and DRY.
If they needed constant oxygenation under all conditions, you'd see tiny vent holes in every threaded part that stainless bolts went into. And, no threadlock or antiseize to gum them up and block the air flow.