Good Point.. frankly I've never thought through the migration of all that moisture we try to put back into the air, inside the house - in Winter - 'cause our bodies really hate 20% RH. A house is a gigantic chem-lab and enviro chamber; 50+ years ago - this was all magic.
But we all realize which direction hot-air goes, so it sounds as if there must be some standard attic air-flow treatment (perhaps fans with solenoid-op shutters?) which can get the air + water out befor the lower life forms move in and colonize. I do recall hearing the consequences of putting-in insulation WRONG-way around for the vapor barrier, though! So.. little things mean a Lot!
Luck,
Ashton