Quite true. I think they can turn into a fairly serious issue, but you'd probably have to keep your soil consistently moist and have no pest management whatsoever. Even then, I couldn't imagine they'd be capable of killing an adult plant.
More than anything, I just find flying buggers annoying, so I take steps to minimize their existence in my house
I find your DE defensive perimeter intriguing, but wouldn't do this myself. I have a good population of house centipedes that I'd like to keep around, as they're supposedly good hunters. Hopefully they continue to stay away from the worm farm.
I've got a spare squirt-bottle, though -- will most certainly give that a shot for dusting containers.