If you use them as vocal mics, they'll be colder than the breath. If the room is not climate controlled, or you adjust relative to the outside temps to save some cash. If the room is a vocal booth and it gets up to 98.6F and humid while tracking. If your studio is/was in New Orleans. If if if if if... But then again if you never use the mics, keep them sealed up, have some form of de-humidifier in the studio and other things. But I think the original point was that a ziplock bag doesn't breathe and doesn't allow for evaporation of already existing humidity on the capsule. If you seal that up, you'll get mold issues.