I agree(ducks).
So far, my experience proves this out to be true. I have over 80snakes, been keeping them in RB and JJ racks. While I have melted a few holes for more air circulation, and open the racks once a day, the humidity is high and I have great sheds from all of my animals (including the girl who had her back chewed up and given to me) and no cases of R.I to this date..over 3 years so far in the racks. I clean once a week (they are on Aspen substrate) to keep down mold and dry out the substrate. I stopped using paper as a substrate, because it gets wet too fast.
I am more of the mind that it's high humidity combined with OTHER FACTORS that may be a cause of some forms of R. I. because, too low humidity has consistently caused R.I (in tanks)..and since there is no perfect set up...and no one knows exactly what percentage of humidity is perfect for BPs, I prefer to err on the side that hasn't been a consistent factor in R.I. cases.