You're obviously in the minority, in terms of being able to service your own gear; and, kudos, that you were always able to soak your disconnected regulators without any water intrusion; but the bulk of gear that I have serviced, over the years, hasn't fared remotely as well as yours; and the rate of interior corrosion of unfinished brass has often proved spectacular -- so much so, that on one occasion, a regulator became unusable, do to heavy pitting of interior sealing surfaces, especially an HP port, where the o-ring would no longer provide a reliable seal . . .
Thankfully, the pieces of crap that have passed for Poseidon dust-caps, over the years (hollow plastic w/o o-rings), have all-but ensured that I soak my gear while it remains pressurized . . .