Badger, as with boar, can come in varying densities of knots. The denser the hairs/bristles are packed, the stiffer the backbone, and also the less product that the brush is able to "soak up" during the lathering process, and also able to release onto the face when applying. When you get a big knot with a super dense badger, it can take a lot more product to do your shave, as a large portion of product & lather will be locked into the dense brush.
I'm sure it makes for a wonderful feeling, warm shave in the winter, thought!!!
Brian - I think it would be totally inappropriate for me to even contemplate what I am thinking about.