That's correct. My boyfriend had them shipped from BHB to my friend Patrick who quarantined them there until Christmas for him. I know for a fact they did not come from Patrick, as I've personally seen his entire collection many times and in the 15 or so years (correct me if I'm wrong Pat) he's been into reptiles he's never had a mite.
Edit: I must add that the two I got from Patrick that were not in contact with the 3 BHB snakes are mite free....
I got 1.1 yellow bellies and 0.1 fire from BHB, and 0.1 lesser and 0.1 pinstripe from Patrick, only the 1.1 yb and 0.1 fire have mites.