Once while taxiing for takeoff, a guy was landing deadstick and I didn't move my avistar away fast enough. He hit the left corner of my horiz stab and there was a fine crack just ahead of the tail group. You're right that there is some weakness there but it doesn't fail in normal circumstances. The covering was split along the crack so that I can see the wood underneath a little. It was a butt joint and that explains the weakness. Repair took me couple of hours. Compressed the crack, and applied thin ca along the crack line . Then I cut three 1-inch strips of carbon strips, remove some covering on the left, right, and bottom sides of the fuse across the butt joint, used thick ca and glued the strips down. Looks "pro" and no problems since.