fig-8's do not need to be backed up, but....
consider what backing it up with half of a dbl-fisherman's would do should one botch the fig-8 (as has oft happened). I could tie in with an overhand knot, and if it were backed up as described it would still be sound....a bitch to untie, but safe.
Dude. Wrong thread. This thread is for making fun of the mountaineers. Which, as we all know, never gets old.