Couldn't find the original post, but there was a bit of discussion about sil-nylon "leaking" or "misting through" some time ago.
This past Saturday, during a hang in the wilds of northern Pittsburgh PA (my Father's back yard!) I awoke to find the underside of my WB SuperFly lightly coated with moisture. There were a few light showers overnight, nothing to get excited about, and my WBSF is pretty new (only a few nights out).
But the conditions were very humid, with temps falling from the 80s down to the mid-60s. I simply wrote it off to condensation due to the atmospheric conditions. I wonder how many complaints of "leakage" or "misting through" are due to simple condensation?