What Bob said. I don't cook them often, but I long ago gave up on the membrane on bbr's. It's just a pain, and, as noted above, it is more prone to tearing easily than the membrane on pork ribs. I either will score it, or just ignore it completely. I'm generally ignoring that side of the rib when I'm chowing down anyway, so it doesn't bother me much. Scoring will help some rendered fat drain off, so worth the small effort.
Rich