Yesterday I was looking over my Flying Scot jib.  I had not removed the 2:1 jib sheet harness at the end of the season.  On first glance it looked new but as I was about to place it with my jib sheets one of the blocks moved towards the opposite side of the brummel loop.
Hidden under the frame of one of the blocks the line had frayed through one of the two loop strands. 

I'm sure this would have failed at the worst possible moment, when one of my Fleet 163 buddies is breathing down our neck as we approach the finishing line!
I'll make a new harness for the upcoming season.
Anyone else have a good "how did that happen" story?