Actually, I do it for the reasons I gave.
I agree...it helps keep dust from falling down into the capsule....though, you'll get dust into it no matter which way it's facing. Dust tends to swirl all around rather than fall from above.
I usually will "bag" my mics when they are on the stand between takes/sessions...like if I'm coming back later or tomorrow and don't want to remove the mics.
I just place a larger bag over the top, but leave the bottom wide open so the mic can "breathe".
AFA moisture and flipping a mic upside down....mmmmm...not sure how much it reduces that? I think moisture is more of an issue with taking a "hot" mic into a very cold environment or vice versa.
With the cable issue...are you hanging it from above somehow?
I have a few mic "stands" that are actually mounted to the ceiling in key spots (so I don't have as much floor clutter)...and yeah, for them, it really helps get the cable up and out of the way…I have the cable running up and across the ceiling and down the wall.
Though with a typical floor stand...no matter how you face the mic...the damn cable still ends up running down the stand and onto the floor.
I still think some newbies just flip the mics upside down ‘cuz they seen it like that in some magazine studio picture.
Oh...and yeah...fix that damn avatar...flip the mic around!