I was a member of the BSA about 17 years ago in Alaska. I carried an old 6 inch Kabar sheath knife (the military pattern with the leather handle) on all our outings and the scout leader never said anything about it. Several of the other boys had sheath knives as well, and of course we all had pocket knives. I have not been involved in the BSA for a long time, but I can't remember the BSA frowning on fixed blade knives. Maybe it was just my troop/pack or leader.