I'm also going to go and say that I know many large scale boa breeders who've had collections for longer than I've most likely been alive.
Here's a nice write up on Pete Kahl's site, probably the world's largest boa breeder:
The snake mite, Ophionyssus natricis, has been found in collections in which IBD has occurred but it is not implicated in all cases of infection.
You have symptoms in your collection? Where did you acquire the boas? How old were they? What were your quarantine procedures? Did you ever have any breakout of mites in your collection? Why would you use (even if disinfected with 9 tons of bleach) a rack that may have ha a "airborne" infected snake in it at any given time for any other snake?